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Chapter Text

Fluorine

Tantrums? Explosions?
First step: Admit the problem.
Electron envy.

Chlorine

Low road or high road?
World War I. Gas in trenches.
Or salt shared, tears shed

Mary Soon Lee

“A terrible crime has been committed!” cried Inspector Carbon, bursting into the banquet hall.

The mingling guests froze with forks and glasses halfway to their destinations and turned towards the door, startled to have the peace of one of Miss Diamond’s famous parties so drastically shattered. In the stunned silence of two dozen elements holding their breath, Miss Diamond’s dangling earrings tinkled softly as she shook her head, as if she had the power to render her brother’s statement false.

“Listen,” said Fluorine, backing away from Barium and twitching his cuffs straight, “it wasn’t me, I wasn’t there, and you can’t prove anything. Anyway, what got nicked this time? By someone other than me.”

“If only it were a matter of simple electron theft!” Inspector Carbon boomed. “No, dear guests -- I do not mean to shock or frighten you, but there has been… a murder.”

Amidst the shocked and frightened gasps of the gathered there came a single skeptical query:

“Are you sure, Inspector?” Silicon pushed her way to the front of the milling crowd, already starting to scribble in the little notebook she always carried for her calculations. “How is it even possible to murder one of us? That fellow Lavoisier conclusively proved, centuries ago, that we can neither be created nor destroyed, so surely murder is off the menu.”

“Shut up, Silicon!” Germanium shoved her cousin for emphasis. “Now is hardly the time for a history lesson!”

“Nor for bickering,” said Miss Diamond coolly. “Tell us, Carbon, what’s happened? Who has been murdered?”

The inspector stood at attention. “Astatine, in the library, by means unknown,” he reported.

“Astatine!” Bismuth gasped, iridescent with dismay. “But I just talked to him -- not even an hour ago! I told him it was such a rare treat to see him joining us for one of these dinners, and now… you say he is gone? How terrible! How tragic!”

“Astatine!” Fluorine snorted at the same time. “That jerk! I bet he faked the whole thing. And if he’s gone, it’s not because he’s dead, it’s because he’s scarpered -- he’s always making himself scarce, especially when there’s work to be done.”

“You will speak of our fallen comrade with respect!” Miss Diamond said sharply. “But, Carbon, I still do not understand. What happened to Astatine? How can you be sure that he is no more?”

Inspector Carbon stood aside and beckoned to the figure behind him in the doorway. “Polonium here came to find me right after. He was hidden in a corner of the library when it happened, and saw the whole thing.”

Polonium stepped forward, hunching his shoulders under the collective regard of the gathered, ducking his head into the folds of a gray scarf swathed about his neck. “I’m afraid I did not see anything, only heard. I’d been reading quietly in the corner, and when the commotion started, I hid behind the shelves and did not dare look until everything was over.” He shuddered as he spoke, his unkempt gray hair falling over his forehead, as if to block out the frightening memories.

“Why don’t you tell us everything from the start,” said Professor Buckminsterfullerene, perking up at the sign of a proper mystery.

Polonium obliged: “I came into the library-- oh, I think maybe an hour and a half ago?” He glanced vaguely down at his hands, clasped in front of him around a slim volume, and lifted it up. “I was looking for this monograph, and once I found it, chose a chair in the far corner, behind some angled shelves, where I wouldn’t be disturbed, and lost track of time.

“I noticed when Astatine came in,” here Polonium once again glanced down at the monograph and off to the side, “He called out hello and I believe I answered him back. He settled down to read quietly somewhere out of my sight, until…” Polonium took a convulsive gulp and ducked deeper into the folds of his scarf. “I heard the library door open again – it’s got a little creak – and then a terrible shout. I couldn’t make out who was shouting, or what they said -- it was a sound of pure rage. I fell to the floor between the shelves and lay there, but I heard Astatine cry out in recognition -- ‘You!’ he said, ‘You’ll never get away with this!’ But the other voice, distorted by madness, cried, ‘I shall have my revenge! Prepare to die!’ And then there came some kind of terrible explosion-- I was knocked unconscious, I think, or maybe just fainted from the shock, and when I came to, the library was in shambles, and there was no sign of Astatine -- or of his remains, for I fear no-one could have survived that.”

“So that’s what that sound earlier was!” exclaimed Silicon. “I thought something had blown up in the kitchen again.”

“We must examine the library for clues at once,” announced Professor Buckminsterfullerene. (“And also for structural damage,” Titanium added quietly, but everyone ignored her.)

The elements followed the Professor down the turns of the long hallway. The massive doors of the library had been left open, and they could plainly see the chaos inside: chairs and shelves overturned, books scattered, and a large, mysterious black mark marring the surface of one wall.

Beryllium required smelling salts to recover from the sight. While Doctor Iodine fussed around him comfortingly, Professor Buckminsterfullerene directed the collection of clues around the ruined library. He set Cesium to compose a detailed time-table of occurrences based on Polonium’s testimony and anything relevant anyone else remembered. The Viscount of Krypton, who dabbled in natural history, took out a measuring tape and mapped the distance between the black spot on the wall and various overturned chairs, frowning in concentration. Inspector Carbon, trailed by Titanium and Tungsten, crawled over the floor, collecting pages torn out of books in case they might contain some useful evidence. Silicon intermittently poked at the black spot on the wall thoughtfully and scribbled things in her notebook.

The others observed them from the hallway, speaking in hushed voices.

“But who would do such a thing to one of our own!” Beryllium wept quietly into Chlorine’s borrowed handkerchief.

“Who could have even managed a feud with Astatine, when we saw him so rarely?” Bismuth lamented.

Hydrogen, the butler, cleared his throat discreetly.

“When Astatine just arrived, I showed him into the billiards room, and-- Miss Diamond, I should never say if it were not for such a tragic event, but I heard through the door a brief but loud quarrel.” He paused, clearly struggling to overcome the fundamental propriety of his profession. “A quarrel with Fluorine, if I may be so bold as to say. It sounded like old business -- the argument started up right away.”

“What quarrel? What argument?” Fluorine scoffed as the other elements edged away from him. “I hardly had a chance to say anything before Astatine dashed off again, and I had no interest in quarreling with him in the first place.”

“He started shouting at you from the moment he walked through the door,” Hydrogen said sternly.

“People are always shouting at me!” Fluorine retorted, before realizing this was, perhaps, not the best defense.

“And where were you--” Inspector Carbon consulted Cesium’s timetable, “Forty-six minutes ago, when Astatine was murdered?”

“We all saw you slink into the banquet hall late,” Beryllium accused, “after Nitrogen served the salad course.”

“Um,” said Fluorine, with a furtive glance at the Earl of Argon.

“That’s right, Fluorine did sneak in late again,” Germanium recalled. “I remember he was suddenly lurking about Aluminium as she and I were talking. But then the door opened again, and… Who was it that came in that time? -- I can almost see it in my mind’s eye…” She drummed her fingers on her reticule in an effort to concentrate. “Oh! It was Chlorine…”

Beryllium cried out and threw down the borrowed handkerchief as if it had been bathed in poison.

“Oh, quarks!” he said in tones of horror, “Just before Miss Diamond summoned us to the banquet hall, I was passing by the Blue Room and overheard Chlorine arguing with someone within. I didn’t recognize the second voice at the time, but it was Astatine, I realize that now.”

“Did you quarrel with Astatine earlier, Chlorine?” Inspector Carbon demanded.

“We did argue in the Blue Room,” Chlorine said evenly. “It was nothing new, and nothing to do with Astatine, in truth. I had made up my mind on a course of action, and he tried once more to dissuade me from that course, but the decision was mine, and long overdue, and no argument would sway me from it, which I tried to make him understand.”

“That all sounds pretty enough,” said Inspector Carbon. “But where were you forty-six–”

“Fifty, Inspector,” Cesium corrected him respectfully, consulting her schedule and the clock on the library wall, which had miraculously survived the destruction.

“Thank you, Cesium. Where were you fifty minutes ago, Chlorine – when Astatine was murdered in the library?”

“In my room, alone with my thoughts.”

“Right,” said Inspector Carbon, staring balefully at Chlorine and Fluorine in turn. “Both those stories sound extremely suspicious.”

“Indeed,” Professor Buckminsterfullerene cut in, “it would appear that both Chlorine and Fluorine had motive to want Astatine to come to harm -- whatever it was they quarreled about, which neither will admit. And we know they had the opportunity for it, since neither has an alibi. As for the means, they are always getting up to dangerous things, poisons and fires and explosions and the like -- and that’s the stuff we know. There is certainly worse we’ve never heard about, from their time in the war.”

“They are too dangerous to let roam free,” Inspector Carbon decided. “What if whichever one of them is responsible should decide to go after Polonium next, as the witness?” (Polonium shrank further down into his scarf, nearly disappearing between it and his mop of hair, and nervously rubbed his wrist.) “Or what if they attack the people who overheard their quarrels, in case they remember more details?” (Beryllium swayed on his feet and clung to Hydrogen, whose expression remained stoic.) “Or perhaps they will set their sights on those of us investigating the crime, to thwart the process of justice?” (Professor Buckminsterfullerene puffed out his prodigious belly, clearly intrigued by the possibility of a showdown with a master criminal.)

“We must ensure the safety of our remaining guests,” Miss Diamond agreed. “Tungsten, Titanium, lock them up in their rooms and make sure any threat they pose is neutralized.”

“Everything’s gonna be neutral as distilled water, ma’am,” Tungsten promised, rolling up his sleeves.

Chlorine submitted to be led off by Titanium with no further argument. Fluorine made a dash for it, of course, but Hydrogen seized him before he could escape the press of elements, and Tungsten marched him down the hall.

“Come on, W,” Fluorine said, once Tungsten deposited him in his room and put his broad back to the door, barricading the exit. “You don’t actually believe all this stuff about arguments and murder. So just… walk out and say you locked me in, and anything that happens after that is not your concern. Come on, for old times’ sake?” Fluorine batted his eyelashes beseechingly. Tungsten conspicuously failed to melt.

“And after we’d had such a good time at that to-do of Silicon’s,” Fluorine groused. “Come to think of it, Chlorine and Ti did too, didn’t they? If not quite so… prodigiously,” he added with a wink. “I thought we had a real connection, a real bond.

“Fine, be that way!” he shouted, as Tungsten shut the door behind him with finality and the key turned over twice. “Not like I ever needed anyone’s help to get out of a tight spot.”

*

A quiet click distracted Chlorine out of his glum concentration on the wall across from his chair. He looked towards the sound and was greeted by the sight of Fluorine, holding a finger to his lips, the supposedly-locked door of the room pristinely shut behind him.

“How did you get in here?” Chlorine demanded in a fierce whisper. “And why have you come?”

“Oh, you know me,” Fluorine whispered back, “always weaseling out of one place and into another. Spare me the pearl-clutching, coz. Obviously I’ve come because we need to figure out what to do about this mess before that dolt Carbon gets any more bright ideas. So, what are you thinking?”

“How can you be so sure that Carbon doesn’t have a point?” Chlorine asked.

“Oh please,” Fluorine gave a quiet snort. “The only way Carbon could have a valid point is if you stuck him in a pencil sharpener and turned. He’s an idiot; trust me, I count on it on a regular basis and it hasn’t steered me wrong yet. I know I didn't off Astatine -- wouldn’t know how to, for starters. And if you’re trying to say that I should believe you’re the one who did it -- I don’t. Not your style. You probably would have challenged him to a duel, or some nonsense like that.”

“You know there was no chivalry in what I did in the war,” Chlorine said grimly. “Not a muon of it. So don’t be so quick to dismiss--”

“Look, coz, I didn’t come here to indulge in your neuroses,” Fluorine cut in. “The war was a dirty business, no-one’s denying that, not even me. But I know you weren’t in it to get your jollies off, or for the excitement, or even,” Fluorine tapped himself meaningfully on the sternum, “to get out of a sticky situation. It was all for the Ideals of Chemistry, a full octet and the Pauli Exclusion Principle, all that jazz. I should know -- I could barely stand to be around you, with all that fervent belief in a brighter future coming off you in waves, in particles, even.”

Chlorine favored him with a bitter smirk. “All right, so you’ve convinced yourself I’m not the murderer. What reason do I have to trust you?”

“Not my style either,” Fluorine said easily. “Flash, bang, broken furniture everywhere, in front of witnesses. If I went to the trouble of figuring out how to murder an element, you can be sure it would be a lot more subtle than that.” His eyes assumed a slightly dreamy look. “Leach his strength away quietly, over the course of days, so no-one would know anything was wrong, let alone who had been there when it started. Melt his bones from the inside, sort of thing. What are you looking at me like that for? I told you I didn’t kill him.”

“Believing you that you did not murder Astatine and being willing to trust you in this predicament are two different things,” Chlorine said tightly. “And you’ve given me very little reason to trust you, coz.”

“Are we on about the Sodium thing again, cousin? Really? I’ve told you a million times, there was nothing between us -- and for once I’m telling the truth when I say that. Purely a business arrangement, Nat and I. Lovely little dental practice. What?” he shrugged. “I’m good at teeth. Nat was good at helping me be good at teeth. That’s all that really ever was, honestly and truly.”

Chlorine’s expression remained skeptical, so Fluorine babbled on. “Don’t get me wrong, I love Nat, Nat is great, salt of the earth, that one -- but I always knew how the two of you felt about each other, and got no reason to mess with a good business relationship, do I? If Nat didn’t tell you the same thing, it’s bound to be on account of feeling insulted that you needed anything like an oath to trust her, and she’d be right about that. Besides,” Fluorine continued with a sly smile, “you know Calcium’s always been the one I couldn’t stay away from. Twice the valence,” he added with an abominable two-handed gesture and an equally horrible wink.

“Enough!” Chlorine’s hushed bark startled them both, and they sat in silence for a few moments, to make certain no-one came running to investigate. Then Chlorine continued, still flushing a luminescent blue-green:

“Just, stop talking about Sodium and valence. Ideally, stop talking at all. I… believe you. As ill-advised as that sounds. And I concede that there is some benefit to us working together to clear our names. You do have certain… skills--”

“Which have already proven useful in this, as you termed it, predicament,” Fluorine pointed out cheerfully, gesturing expansively at the door of Chlorine’s room.

“You do have certain useful skills,” Chlorine continued doggedly. “But do you have any idea how to go about the task of proving ourselves innocent? If neither you nor I murdered Astatine, who did?”

“He seemed awfully intent on making enemies lately, didn’t he,” Fluorine mused. “Showing up here for once, having shouting matches with people at every doorway... What were the two of you arguing about, anyway? And don’t give me any of that--” Fluorine assumed a dramatic, nobly mournful stance and expression, “‘it was my own lonely business and no sensible argument would sway me’ stuff.”

To Fluorine’s surprise, Chlorine did not seem to take offense or be inclined to argue. “You might as well know,” he said, “because if it’s anybody’s business but mine, it’s yours. Maybe more than mine, actually, given how much of the work was yours. And perhaps I should have asked you beforehand, but I couldn’t live with it hanging over my head as a secret anymore.”

“What are you going on about?” Fluorine frowned. “What business of mine? Oh! Oh.”

They stared at each other in silence for several moments.

“You are planning to go public about the… Substance, aren’t you,” Fluorine said quietly. “That’s what you meant about it being my business too. My work.”

Chlorine nodded. “It was never deployed offensively, it’s true, but that’s what we were working towards -- or at least I was, even knowing all the horrors that would ensue. If the others are going to judge me for what I did in the war, let them judge me by the worst of it. And when it comes to the moral burden of that work, intent carries every bit the guilt of completion.”

“I will respectfully disagree with you there, you weirdo,” Fluorine muttered.

“Well, I believe it, and have decided to act on that belief. And whatever he may have intended, I feel grateful to Astatine for helping me come to that decision.”

“Helping you come to…” Fluorine echoed faintly. “Wait a minute, Astatine was blackmailing you too?!”

Chlorine gave a terse nod. “I don’t know how he found out about the Substance, but he came to me several months ago and threatened to go public. I… panicked, I suppose. Couldn’t bear the thought of having to confront it again, with the others knowing, instead of it sitting in the space between my head and the wall.” He fell silent, staring past the floor. Fluorine put an awkward hand on his shoulder and squeezed lightly, for once out of chatter.

“I’m ashamed to think of it now,” Chlorine continued quietly, “How long it took me to realize that others knowing was a good thing. The right thing. But I understood, finally, and the last time I saw Astatine -- the last appointed time, before today -- I told him that I was going to tell everyone myself.”

“Probably thanked him for helping you come to that epiphany, too,” Fluorine said, with something almost like fondness. “Wow, but it never ceases to amaze me how some elements are almost too stupid to exist.”

“I didn’t thank him,” Chlorine said stiffly. “I left while he was haranguing me about choosing to ruin my life for nothing.”

“Such a thoughtful blackmailer, yes.”

“I wasn’t expecting to see him again -- you know how he is -- but when he came into the Blue Room today, it was more of the same. He started shouting that I was throwing my reputation away for no good reason--”

“Stupid to have a fight over keeping a secret in a public place. I was thinking you’d been the one to start it…”

“Thanks,” Chlorine said drily. “What was he blackmailing you about, then?”

“You mean, what am I insufficiently shameless to care about people knowing?” Fluorine laughed. “Good question. Very banal, I’m afraid -- affairs of the heart, or thereabouts. Astatine knew I was trying to make a go of it with Neon and threatened to tell her I was not being entirely faithful. You know what these noble gas types are like, want to think they’re the center of the universe.”

“And you went along with it?” Chlorine asked skeptically.

“It was kind of fun for a bit -- nobody had tried to blackmail me before. But the novelty wore off, and I was getting pretty tired of Neon anyway. Too much fawning and flattery required, ‘you light up my life’ and all that nonsense. And I was thinking it was time to move on to Helium anyway.”

“Setting your sights pretty high, aren’t you! Even you couldn’t get a rise out of Helium.”

“You know me, never back away from a challenge,” Fluorine replied cheerfully. “So, anyway, I told Astatine where to shove his threats. He might’ve tried to give me some spiel about how I was making a mistake, too… He definitely did give me an ultimatum -- two hours to think about it one last time before he went to Neon with the pictures -- Magnesium’s work, I think, they were actually pretty good; Astatine was not amused when I asked him for copies, but I’ll just get them from Mags later myself.

“Anyway, two hours -- I remember because he kept jabbing at that watch of his, the nice shiny one he was forever flashing about on his wrist -- like he always had somewhere more important to be, you know? So to be honest I may have stopped listening before then, and once it looked like we were done with the ultimatum part, I walked out. I was real surprised when he started after the same thing again here; had thought that was all sorted and we had both moved on, since it was clear I didn’t give a damn who he told what.

“Kinda wish I’d taken the time to nick that watch, though,” Fluorine added with a tinge of regret. “It was a nice piece, and now it’s probably blown to smithereens, along with the idiot as was attached to it. That’s a pity.”

Chlorine shut his eyes and shook his head, as if trying to clear a bitter taste from his mouth.

“Maybe Astatine was getting desperate to keep the blackmail going,” he said. “Not just with us -- maybe he pushed someone else too hard, someone with more to lose… and paid the price.”

“So anyone could have a motive then,” Fluorine said, catching on, “since the motive would be a secret. And we can’t figure out who could have the means since we don’t know how they did it. So that leaves the, whatsits, opportunity, right?”

“Who else was not in the banquet hall when it happened? I didn’t see anyone else when I was walking up, just the door closing after you.”

“Well, Argon, but I can vouch for him. Hydrogen and Nitrogen, going about their business, but I bet they would have been missed if one of them had snuck away for a spot of murder.”

“Inspector Carbon himself?”

“Nah, he’s an idiot. He’d never be able to pull off something like that, or if he did, he would’ve bragged about it to everyone immediately.”

“You’re… not wrong.” Chlorine said with a snort. “What about Polonium, then?”

“Now there’s a thought! What do we know about him, really?”

“He’s not been around much before. Keeps to himself. I think it may be only the third or fourth time I’ve seen him, and only in passing, smoking in the gardens, for the most part, or passing through the banquet hall.”

“I can’t say I’ve seen him around much more. And he was acting twitchy as hell just now, with his stupid pamphlet and his stupid scarf.”

“That could easily be the shock of witnessing the attack,” Chlorine pointed out in the spirit of fairness.

“Could be, but he’s still rubbing me the wrong way. How about I go and poke around a bit? See what I find?”

“I doubt I could stop you, if two locked doors can’t,” Chlorine said. “Nor do I wish to stop you, in truth. Polonium does seem to be the best lead we have, the one strange thing that may not directly involve Astatine himself.”

Fluorine sketched out a jaunty salute, for old times’ sake, and slipped past the door, which shut after him with another faint click.

“Be careful,” Chlorine whispered to the closed door after a moment’s silence.

*

Miss Diamond, possibly out of sheer ostentatiousness or perhaps some sense of noblesse oblige, insisted on maintaining rooms for any element that had ever stayed at the mansion as a guest. Fluorine could not remember where Polonium’s room was, only that it could not be near any of the ones he visited habitually (which visits called for discretion whether their owners were out or in, and thus it paid to be aware of their neighbors). He went through perhaps a dozen by trial and error, not finding Polonium but acquiring a few useful small things in the process (one never knew when a pair of cufflinks or a jeweled letter opener might come in handy). When he finally found it, Polonium’s room was empty of its infrequent resident and devoid of anything interesting, just several dusty volumes from the mansion’s library with abstruse titles about electrical something or other.

Fluorine snuck through the kitchen, fortifying himself with a filched snack, took a moment to admire the fancy cutlery Hydrogen was polishing industriously, his back turned, then followed the unmistakable lecturing cadence of Buckminsterfullerene’s voice to spy on his conversation with his siblings in the small parlor, from which he learned that Polonium had gone into the gardens to calm his nerves with some fresh air and serene nature.

The gardens were in a state of autumnal senescence, still bright with red and yellow foliage but sparse and largely deserted. It was simple to spot the lone figure sitting on a bench at the far end of the arbor walkway, and simple for Fluorine to creep up behind him, observing him through the filigree of a largely denuded hedge. Polonium was staring at the unopened monograph in his lap (a slim volume entitled “Introduction to Static Electricity”) and rubbing his wrist. Fluorine frowned at this picture, some unexpectedly familiar detail nagging at him, but couldn’t place the sense of oddness.

Polonium was unfortunately not doing anything overtly suspicious, did not appear to be waiting for an accomplice with whom he could have a usefully incriminating conversation for Fluorine to overhear, and did not seem to be about to conveniently confess to murdering Astatine. Amidst this failure of the more conventional investigative techniques -- Fluorine had actually picked up a few from that one-night stand with Carbon, which had been only to get out of a sticky situation, whatever Carbon thought, and never again -- Fluorine fell back on his usual standby and emptied the mark’s pockets.

One look at the spoils, and he was melting silently into the wild parts of the garden and then racing back to the mansion and Chlorine’s room.

*

“What do you make of this?” Fluorine demanded, putting the watch down on the table in front of Chlorine with a flourish. “Oh, and here, I grabbed you a sandwich on my way through the kitchen. You might as well have that now, too.”

“It’s certainly Astatine’s watch,” Chlorine conceded. “At least as recognizable as its owner, since we saw it just as much. I’m glad that your regrets over not stealing it earlier proved ill-founded, but is this really the time to be pilfering a murder victim’s belongings?”

Fluorine jerked back the hand with the proffered sandwich with an offended huff. “I didn’t filch it from Astatine’s room, you ass! The watch was in Polonium’s pocket. I think he really did murder Astatine in the library. And took the trouble to rob him first, which, honestly, good for him, except for the part where the blame for it is falling on us.”

Chlorine frowned down at the watch. “No, something’s not quite right about that. Let us think.”

Fluorine shrugged agreeably and settled down in the chair across from him.

“If Polonium is the one who murdered Astatine,” Chlorine went on, “why report the murder to Inspector Carbon? Why place himself at the scene of the crime, why help establish the timeline of what occurred… Why tell the Inspector who the victim had been, even? Certainly the explosion at the library would have been noticed, and quickly, but what would have connected Astatine to it, or Polonium, if Polonium hadn’t precipitated the investigation himself?”

“When you lay it out that way, it doesn’t seem to make much sense,” Fluorine admitted, chewing thoughtfully.

“I had been thinking of Polonium’s involvement as a crime of passion, a desperate element pushed too far by a blackmailer’s greed. But stealing your victim’s expensive watch before murdering them does not connote a crime of passion to me. Something else must be going on here, something we’re missing... Didn’t you say you’d brought that for me?”

Fluorine reluctantly surrendered the half-eaten sandwich into Chlorine’s outstretched hand.

“There’s something weird about Polonium, I agree,” Fluorine said. “Something about him was making me twitch just now in the garden, and earlier when he was speaking to everyone. The problem is, none of us know Polonium well enough to be able to figure him out. He shows up once in a termolecular reaction, he never talks to anyone, hell it could be a different element under that stupid scarf each time, and none of us would know the difference.”

Chlorine shot out of his chair, which fell over with a clatter.

“That’s it! That is the explanation, the thing we’ve all been missing until now -- it isn’t Polonium under the scarf at all. It must be Astatine.”

Fluorine stared at him in open-mouthed confusion, which slowly transformed into an admiring sort of comprehension as Chlorine went on:

“Astatine, whom most of the crowd see as rarely and briefly as Polonium, and wouldn’t recognize under a disguise. Astatine, whom no-one would have a reason to suspect of any wrong-doing when he was so effectively removed from the list of suspects by pretending to be the murder victim. Astatine, who has never been stupid, yet insisted on staging two noticeable arguments in a public place, ostensibly over blackmail.”

“You mean he was actually trying to frame us for murder? The nerve!” Fluorine said, with no small trace of approval.

“It certainly appears that way. And we might have never guessed if you hadn’t, er, found his watch.”

“Well, let’s--” Fluorine began, but fell silent at the sound of footfalls in the hallway, putting his hand over Chlorine’s mouth for good measure.

“What was that noise just now, Chlorine?” Titanium’s voice called through the door. “You better not be trying to set off another bomb in there.”

Chlorine shook off Fluorine’s muffling hand. “I’m contemplating my complicity in the grand total of universal suffering,” he answered, deadpan. “Sometimes that requires me to throw furniture.”

There was a brief silence, during which Fluorine was clearly trying not to break into giggles.

“Well, uh, carry on,” Titanium said, and they listened to her march off down the hall.

“That was brilliant,” Fluorine laughed once Titanium was safely out of earshot. “Couldn’t have mocked you better myself. So, where were we? Oh yeah, let’s go tell Carbon, or Professor Bucky-balls, or whoever, that Astatine is our baddie, and have the proper miscreant nabbed, for once.”

“You mean, as opposed to you getting away scot-free most of the time? That would make for a refreshing change,” Chlorine smiled. “But aren’t you forgetting something?”

“Can’t imagine what,” Fluorine said. “You’ve already eaten your sandwich.”

“Half my sandwich. But that’s not what I meant. There was still the explosion in the library. We now believe Astatine was its perpetrator and not its victim, but we cannot conclude that it claimed no victim at all. We know that Astatine was Astatine before the explosion, since we both spoke with him and Hydrogen let him in. But Hydrogen was not surprised by Polonium’s appearance as a witness, so Polonium must have arrived in the normal way, too -- the real Polonium.”

“Well, sure, so Astatine offed him in the library and put on his scarf. Isn’t that what we already decided?”

“Silicon didn’t think it was possible to murder an element, and she tends to be right about most things she says. What if Polonium isn’t dead, but held out of the way somewhere while Astatine executes his scheme? If we go to the authorities, if Inspector Carbon’s questioning spooks Astatine and he runs -- we do know he’s awfully good at disappearing -- we may be condemning an innocent element to more unknown suffering until we find him. Perhaps…,” and here Fluorine was cheered to see the hard glint in Chlorine’s eyes, familiar to him from the war, “Perhaps our best chance for a resolution that minimizes harm is to encourage Astatine to confess and free Polonium on his own, if indeed the crime is abduction and not murder..”

“Encourage him, right!” Fluorine chirped, getting up. “Well, let’s go and be encouraging, coz.”

*

Encouragement ended up having to wait almost two hours, until the impostor returned to Polonium’s room. Chlorine and Fluorine, concealed behind a folding screen, swiftly abandoned their latest listless game of Lewis dot structures when the door started to push open after a brief fumbling of keys.

Glancing furtively over his shoulder, the false Polonium stepped through and hastily shut the door behind him. He had just put one hand in his pocket and lifted the other to unwind his scarf, when Fluorine stepped out into the open.

“Hello,” Fluorine said cheerfully, dangling the watch in front of him by the strap. “Looking for this? Or were you going for some other loot you’d taken off your victim’s corpse?”

“Polonium” whirled back to the door, but his dash for freedom was arrested by the sight of Chlorine leaning against it, solidly barricading the way.

The two of them eyed each other in silence for a long moment. The newcomer was the larger and heavier of the two, but Chlorine’s reputation carried some weight, so with a sigh the false Polonium backed down.

“Nice trick you pulled there,” Fluorine went on. “Murder Astatine yourself, pin it on us. Might’ve managed it, too, if you hadn’t gotten greedy with the watch. Nice for you that we figured it out first, instead of Carbon or the Professor. You know, we people who are prepared to be reasonable, and were not that fond of Astatine to begin with.”

“I’m not here because I’m prepared to be reasonable,” Chlorine interrupted coldly. “Or to play a part in this charade,” he added, with a level look at Fluorine. “I’m here because I believe these are the circumstances in which you’re most likely to tell the truth, Astatine.”

“Right.” Astatine straightened up, stripping off the scarf and the disheveled gray wig with an expression of distaste and dropping them on the floor. “So what do you want, then? A spot of blackmail of your own?”

“Well, turnabout is fair play, as they say,” Fluorine shrugged, tossing the watch up in the air and catching it at the last moment to make Astatine flinch. “You could hardly complain if we were here for that.”

“Don’t pay attention to Fluorine or his little jokes,” Chlorine said. “We’re not here to blackmail you as Polonium or as Astatine.”

“Then what do you want, exactly?” Astatine asked, unable to keep his eyes away from the tumbling flash of the watch Fluorine was now carelessly juggling alongside a pen knife, a crystal stopper, and a tangerine he had produced from somewhere within his pockets.

“To know whether Polonium is alive. If he is, to be taken to him so that we can release him. And if he is not, a full confession, which you will deliver to Inspector Carbon when we take you to him, immediately.”

“Of course he is alive,” Astatine scoffed. “Do you think, if I had found a way to excise an element from existence, I would waste it on eliminating one that was already half a ghost? Or on framing a pair of lowlifes and has-beens?”

“Who are you calling a has-been?!” Fluorine cried, fumbling in his indignation and finally catching the watch a handbreadth above the floor as tangerine, knife, and stopper bounced chaotically around him.

“Me, I think,” Chlorine said with a cool smile. “Enough nonsense, Fluorine; put those away. Astatine, take us to where you’re keeping Polonium imprisoned.”

“Prison” was certainly too lofty a word for the closet Astatine led them to, tucked away at the end of a dusty hallway on one of the upper floors, whose rooms even Fluorine could not remember having ever visited. Fluorine picked the lock while Astatine fumbled to find the right set of keys.

Under Chlorine’s stern observation, Astatine himself untied his victim. Fluorine removed the crumpled handkerchief that Astatine had used as a gag, taking a curious sniff. “Your work, I think,” he said to Chlorine, who nodded with a sour expression but little surprise. Extracted from the closet and leaning against the wall, the real Polonium was looking grayer than they remembered from their previous brief encounters, but didn’t seem to have been harmed by the ordeal. Fluorine looped the scarf he’d brought along around Polonium’s neck, tying it into a jaunty bow, and gave Polonium a firm pat on the chest just beneath it. “Good as new.”

“Indeed, indeed,” Astatine ventured. “And no harm done. He shouldn’t remember what happened, and nothing ultimately did, so perhaps we’ll let bygones be bygone and go about our separate ways…”

“I’m afraid I have to insist on us all going a single way,” Chlorine said, “and that is to report to Inspector Carbon exactly what happened, from start to finish.”

*

Under the aegis of Miss Diamond’s firm insistence and with the help of Hydrogen’s element-herding prowess, Professor Buckminsterfullerene gathered all the residents, guests, and house staff in the banquet hall for the resolution of the mystery.

While Astatine, hands bound in front of him, under guard by Titanium and Tungsten, stared blankly ahead of him and the still-shaken Polonium smoked convulsively and snuggled into his scarf, Professor Buckminsterfullerene informed the others of Astatine’s blackmail scheme and the plan to frame one or both of them for murder once that scheme had fallen apart. (Fluorine shot Magnesium a thumbs up and a wink when the compromising photographs were mentioned, and Chlorine insisted on revealing to everyone the details of his war-time work on the Substance, which failed to generate any cries of horror from elements eager to hear the mystery of the fake murder resolved.)

A forged invitation which Fluorine had found in the real Polonium’s pocket, with a personal invitation from Miss Diamond for an intimate gathering before the banquet, explained how Astatine had gotten Polonium alone in a secluded room, where he was able to stun his victim with a knock to the head, drug him into unconsciousness, and lock him away.

“To think,” Miss Diamond said frostily, “that someone should so take advantage of my welcoming nature and my reputation for generosity. I will not soon forget it.” Astatine, who had been listening to the recitation of his machinations with a resigned but unrepentant air, paled considerably, and even Professor Buckminsterfullerene paused his flow of deductions.

“Oh, I shudder to think what would have happened to poor Polonium if the ruse had not been discovered!” Beryllium exclaimed. “What a cruel fate to subject a fellow element to, and for no reason other than utility to an unrelated evil plan.” He dabbed at his eyes with a fresh handkerchief borrowed from Chlorine.

“With Polonium safely trussed up in a closet,” the Professor went on, “and the public arguments with Fluorine and Chlorine witnessed by trustworthy elements, the groundwork was laid for his final ploy. It was at this point that Astatine went into the library, taking care to be observed entering. He was counting, no doubt, on Fluorine’s well-known proclivities and Chlorine’s solitary nature to ensure that at least one of his targets would not have an alibi during this critical time. Astatine staged the scene of destruction we all witnessed, disguised himself as Polonium using a wig and the scarf he had taken from his victim, and ran immediately to find Inspector Carbon.

“And perhaps his disguise would have worked to fool the simpler minds among our number,” Professor Buckminsterfullerene continued, “but he had made some fatal errors which were easily apparent to the trained and discerning eye. It was simple to observe that, while our studious Polonium’s room is filled with advanced volumes on static electricity, Astatine had selected an introductory text which would have been far beneath the real Polonium’s notice. It was also apparent that something was awry with the individual presenting himself as Polonium, since he refrained entirely from the use of tobacco. Most telling of all, however, was the way Astatine, even in his Polonium disguise, could not rid himself of the habit of nervously checking or fiddling with the watch that was not there!”

“Avogadro’s extremely numerous balls!” Fluorine hissed indignantly to Chlorine. “This blowhard is trying to claim all the credit for a crime that we solved!”

“So you see,” the Professor concluded, resting his hands on the curve of his belly in a sign of complete satisfaction, “everything about this case has been smoothly resolved through the application of deduction and knowledge of elemental behavior.”

“But why would Astatine do such an awful thing?” Beryllium cried. “What possible advantage could be worth ruining so many lives?”

“Sometimes such questions defy our understanding, my dear,” Professor Buckminsterfullerene said gravely. “Astatine is a fundamentally unstable element, and his reasons may make little sense to us.” Fluorine, who had been making pompous faces throughout the Professor’s explanation, tossed a sympathetic eyeroll towards Astatine, whose flat stare did not waver, but the cold smile he had been wearing twitched up at one corner in minute acknowledgement.

“There is something I’m still confused about,” said Doctor Iodine. “If you would be so kind as to explain, what did happen at the library? Was there an explosion? What was that mark on the wall?”

“Elementary, my dear Iodine,” the Professor began, but did not appear to know how to continue.

“Actually, I can explain that, I think,” said Germanium. “I’ve taken some measurements and performed some calculations, and I believe that Astatine has stumbled upon a fascinating property we had not known about till now. By ejecting a positively charged particle, Astatine released a powerful burst of energy which caused the damage we saw at the library and allowed him to impersonate Polonium most convincingly. Though, of course, not convingly enough to fool a connoisseur of elemental nature like the Professor.”

“Quite elementary, as the young lady said,” Professor Buckminsterfullerene repeated, inclining his head benevolently towards Germanium.

“This is really exciting!” Germanium burbled on. “It’s been theorized that such a thing could be possible, but no-one had seen it happen until now. Now that Astatine has cracked how to do it -- in a very terrible way, of course, what a shame about all the kidnapping and blackmail and fake murder, very bad, all that -- there are so many things to try, to harness the energy of this transformation! We must run more experiments at once!”

“Well, at least someone’s happy about all this happening,” Fluorine muttered.

“Yes, I do think one could say that some good things have come out of what happened here today,” Chlorine said, putting a hand on the other element’s shoulder. Sodium caught Chlorine’s eye from across the room, and he held her gaze and inclined his head in a minimalist approximation of a bow.

*

Several hours later, Chlorine stepped into his room and nodded to its existing occupant with an apparent lack of surprise. “Find what you’re looking for?” he asked.

“Have now,” Fluorine said, with unembarrassed good cheer, and left off rummaging through Chlorine’s things to join him at the table. “Actually, I stopped by to give you something I owe you.”

“What’s that?”

Fluorine proffered a small package wrapped in greasy paper: “Half a sandwich.”

“Thanks,” Chlorine laughed. “Why have you actually come?”

“Germanium got me thinking,” Fluorine said, “the way she went on about other things this horrible blasty disguise of Astatine’s could do. Maybe something like that could be done with the Substance, too, now that the others know about it. Silicon could play around with it, maybe -- that lot is always finding uses for the most horrible things, like the stuff Phosphorus cooked up. Or -- Beryllium’s been talking about space -- he’s got a good head on his shoulders, actually, when he’s not weeping annoyingly or fainting away -- and maybe it could come in handy there?”

“I would like that,” Chlorine said slowly, “if something good came from that blighted work, the way truth and a kind of freedom were the end result of the secrets, deceit, and imprisonment of Astatine’s scheme.”

“Would just be nice to have all that work add up to something,” Fluorine sighed. “No argument that it would be even better if that something isn’t completely horrible.”

“Do you think that Astatine will be back after us over this?” Chlorine asked. “As the resident recidivist, I trust your judgment on whether he’ll get away with a slap on the wrist and be back to his old tricks.”

“Not an exothermic reaction’s chance in hell,” Fluorine grinned. “Oh, nobody cares about him blackmailing the pair of us, and Polonium is none the worse for wear, so nobody will care about that, either, after today. But that idiot forged an invitation from Miss Diamond, and used it as a trap for a guest of hers. He won’t be coming back from that any time soon. Trust me, I know which of that trio not to cross.”

THE END

Chapter Text

- Carbon occurs in several allotropes, including diamond, graphite, and fullerenes. The first fullerene discovered was buckminsterfullerene, C60, whose soccer ball-shaped molecules are often referred to as "buckyballs".

- Fluorine has the highest electronegativity of any elements and thus attracts shared electrons more strongly than any other species. (Chlorine actually has the highest electron affinity, though all of the halogens have very high ones.)

- Silicon is foundational to semiconductor manufacturing, the creation of integrated circuits, and thus all computing devices. (Germanium is also a semiconductor, and integrated circuits using both Si and Ge are part of the emerging technology in the industry.)

- Antoine Lavoisier conducted experiments proving the Law of Conservation of Mass c.1785.

- Bismuth crystals are really cool-looking!

- Astatine is the rarest element on Earth (that occurs naturally): "only approximately 25 grams occur naturally on the planet at any given time". It is also very unstable, with the longest half-life isotope having a half-life of only 8.1 hrs.

- Cesium-133 is is used as the definition of the SI unit for time measurement, the second: "The second is the duration of 9,192,631,770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the caesium 133 atom."

- Krypton was used as the definition of the SI unit for length, the meter before being superseded by the speed of light standard. The meter was defined as "the length equal to 1,650,763.73 wavelengths in vacuum of the radiation corresponding to the transition between the levels 2p10 and 5d5 of the krypton 86 atom."

- The noble gases (Helium, Neon, Argon, Krypton, Xenon, and Radon) are relatively very inert and for a long time it was believed that they could not form any chemical compounds. The first of the noble gas compounds to be discovered/synthesized were compounds of Xenon and Fluorine, such as XeF2, XeF4, and XeF6. Fluorides of Krypton also exist, and argon fluorohydride was discovered in 2000. Argon difluoride, ArF2, is predicted to be stable at high pressures. There are no known fluorides of Neon or Helium, although some compounds or ions have been discovered which contain both Ne and F, and the He+ ion can be shown to react with F-containing compounds.

- Chlorine was used in chemical warfare as far back as WWI, both as chlorine gas and as part of the chemical makeup of mustard gas (C4H8Cl2S).

- Distilled water is neutral from the standpoint of the acid/base pH scale (i.e. pH of exactly 7), but over time its pH will become slightly acidic as it absorbs CO2 from the air.

- Tungsten (periodic table symbol W, for Wolfram) is the metal with the highest melting point 3680K (although non-metal carbon has an even higher melting point, by ~100K, and there are non-elemental compounds that are even higher).

- Tungsten hexafluoride and titanium tetrachloride (TiCl4, pronounced affectionately like "tickle") are used in semiconductor industry for thin film deposition of, respectively, tungsten metal and titanium-based dielectric films by chemical vapor deposition or atomic layer deposition. Phosphorus is used as a dopant.

- Pencil lead is made out of graphite, an allotrope of carbon.

- Quarks and muons are subatomic particles.

- The octet rule "refers to the tendency of atoms to prefer to have eight electrons in the valence shell." The Pauli Exclusion Principle states that no two electrons in an atom can have the same four electronic quantum numbers.

- Wave-particle duality is the concept in quantum mechanics that every particle may be described as either a particle or a wave.

- Regarding Fluorine melting bones from the inside, I was referring to the scary stories you hear about hydrofluoric acid/gaseous HF exposure. But here's an interesting experiment showing what happens when a chicken leg is immersed in HCl, H2SO4, and HF (note: it's pretty gross).

- Sodium Chloride (NaCl) is, of course, table salt. Sodium fluoride is used to prevent tooth decay. The periodic table symbol for Sodium is Na, from the Latin name Natrium.

- Chlorine has a pretty spectrum.

- Chlorine trifluoride, ClF3, was explored as a chemical weapon during WWII, but fortunately never deployed. It was referred to as "Substance N" (N-Stoff) by the German scientists working to develop it into a weapon. It was also explored as rocket fuel and is used as a clean gas or etchant in semiconductor manufacturing applications. Here's a fun video about the stuff.

- Magnesium was used in flash photography.

- Polonium-210 is used in manufacturing devices that eliminate static. It is also one of the things that make tobacco radioactive.

- Teflon, (C2F4)n, a polymer consisting of chains of carbons bonded to fluorines (and to carbons) is what makes non-stick kitchen utensils non-stick.

- Termolecular reactions (i.e. reactions involving 3 species) are very rare because they require three separate molecules to collide at the same time with the correct orientation and energy.

- Lewis Dot Structures are fun? kind of like a game?

- Chloroform, used as an anaesthetic, has the chemical formula CHCl3. It would take ~5 min to knock out a person with chloroform alone.

- Anything being counted using Avogadro's constant is extremely numerous indeed.

- Astatine-210 decays to Polonium-210 by β+ decay (positron emission). Polonium-210 decays by alpha particle emission to stable Pb-206 (lead). Nuclear power is generated by the energy released during fission.

- Beryllium is used in space applications.

- An exothermic reaction (one that releases heat) will shift back towards reactants (i.e. go in reverse) if temperature around it is increased, in accordance with Le Chatelier’s Principle.