“I told you I saw him,” she whispers, her fingers to her mouth like a child. She even seems smaller, seems to be shrinking.

“Diane, you didn’t see him.”

“I did,” she says. “But his mustache was gone.”

I take a breath. “Did you know he was up there?”

She shakes her head, a gray film on her face under the light.

“Why would I ever believe you?” I say. “You’ve lied about everything.”

“No, Kit,” she says, the ceiling groaning again above us. “You’ve got it wrong.”

“Could Dr. Severin know?” I ask, my head aching.

“About my dad?” she says, her eyes dark, stepping forward now.

“What?” I say, impatient. “About Alex. Could she know?”

But Diane doesn’t seem to be listening to me. “No one else can ever know. You’re the only one. The only one who knows what I am.”

What I am. What are you, Diane?

My hand shoots out before I can stop it. The slap is almost a punch, a hard clapping sound, so hard she stumbles backward. My palm print on her cheek, a scorch.

“I never wanted it,” I say. “I never asked for it.”

The groan is more than a groan this time.

We both look up at the ceiling panel. Swollen like the belly of a whale.

It seems to take forever, the panel peeling loose like a zipper unzipping.

“Kit.” Diane’s hands are on me, hard, the only time they ever felt hot to the touch.

Pushing, both of us leaping against one wall, her arm around my waist. The scatter of particle dust, the ceiling panel splintering, like the hull of a ship torn loose by an iceberg. The sudden hard thud against me, knocking my feet out from under me, seeing Alex’s blue shirt billowing, hearing the awful thump. Everything falling.

My right hand aches. I’m holding something tight between my fingers.

I’m lying on the floor of the feed room. My face is wet, and my legs, and there’s a coldness all through me. I can’t see from one eye; something’s caught between my lashes.

I blink it loose, look down at my hand, see what is pressed between my fingers: the blue linen of Alex’s shirt. Next to me, the soft limbs of Alex himself. His shirt lifting like a cloud each time the fans pass.

Then what looks like a half-sunken carnival balloon, green and twisted.

Shifting myself, turning, I know it’s no balloon but Alex’s arm curled around itself, the rigor long past. Bloated and blistered and meaty. And something delicate, the poke of a leg, the body folded in on itself. The pants fabric straining, stiff with brown blood, and popping from it a calf, the delicate, almost feminine turn of an ankle.

Alex. Poor Alex.

In that moment, I know if I see his face, I will die.

But there’s no face to see, his body wrapped tight around itself like a Christmas present. The soft black of his soft hair, hair I stroked with my nail-bitten fingers a few nights ago.

You saved her, a voice is saying, deep, male.

No, she saved me, says Diane.

Diane’s face looms above me, that halo of hair lit by a bank of fluorescent tubes hanging by a pair of shredding cords behind her.

The only friend I ever had, Diane is saying.

“There she is.” That male voice again, thick, throaty, familiar. “It would take more than a few pieces of wet fiberboard to knock that brain loose in its skull.”

Serge’s face hovers above me, his cheeks even more distended, an earthy smell coming from his dark mouth.

I try to move, but my neck bends like a plastic straw, and for a second I see stars. I’m on a sofa, itchy and low-slung, in Serge’s pocket-size office, just off the vivarium. The walls are white and bare, a laptop humming on his desk beside a tidy stack of file folders.

“How did I get here?” I say. “You carried me.”

“It was not so impressive as it sounds. I give my choreography a C minus.”

All the lights are off except one plastic gooseneck lamp. Classical music murmurs from a tiny glowing speaker. Through the door, I see the tech kitchenette, barely big enough for a dorm fridge, a narrow sink, a burnt-orange percolator warming itself.

“I should take you to the hospital,” he says, sitting on the sofa arm, “but that is not possible.”

I feel the back of my head, soft and spongy. The smell.

“So you did it?” I say to Serge. “You found the body. You put it up there.”

Serge nods slowly, the snaky trails of a hanging plant dancing behind him as the radiator hisses. “It was not meant to be a long-term solution,” he says. “I pride myself on always finishing my work. The cleaning, the sterilization, swiping his access card so it appeared he left. But this job I could not complete. Some tasks are too objectionable.”

Serge’s words don’t make sense and I wonder if it’s his swollen mouth, the medication from the teeth extraction.

“Disposing of the body as if it were lab waste was more than I could tolerate. I had a crisis of conscience. Surely you understand that. You of all people should understand.”

“I don’t understand anything,” I whisper, trying to sit up. “Why would that be your job?”

“That is my point,” he says, helping me upright on the sofa. “I have sealed off the room. To give us some time to consider things. It’s ten p.m. No one will be here until six.”

“And…Diane?”

His face darkens. He leans back against the wall, one knee up on the sofa arm. I sit up taller, holding the back of my head, which feels like it might peel off.

“She is here as well. She has cleaned herself in the ladies’ room.”

On cue, Diane appears in the doorway, her hands clasped in front of her, a brush of blood on her brow.

“The front of her head, the back of yours,” Serge says to me.

“Together, we’ve got one whole brain,” I murmur.

Serge points Diane toward the only other seat, a metal folding chair with bright red foot caps like painted nails. “Excuse my manners,” he says. “I do not have many guests.”

“Do I smell jasmine?” Diane asks, taking a seat. There’s a look in her eyes I can’t name.

There is something between them. Something fresh and nasty.

“Good nose,” he says. Then smiles. “Look at me. As I say, I don’t have many guests. I’ve been having tea. Would you like some?”

We sit for a moment in silence as Serge moves around in the kitchenette, his hands like long-necked birds. I can’t figure out what’s going on, but something’s happened between them.

“We must let it steep four minutes,” he says, resuming his perch on the sofa arm.

Diane is staring at the floor intently, a look I do not like. It reminds me of long ago, the shag carpet of my bedroom, her dark words. I wonder what they’ve been talking about.

I feel a rush of heat to my eyes. What are we doing here?

Serge reaches for his phone and raises the volume on the music, which suddenly fills the small space.

No one says anything for a moment, and Serge closes his eyes. He’s humming to the music, making little pit-pit sounds, his voice rising from a near whisper to a full-throated hum.

“What is this?” I say, a feeling in my chest as the music soars mournfully. “I know this song.”

“Saint-Saëns,” he says. “‘The Swan.’ It is, I suppose, what some call kitsch. But I find it appealing.”

“I never knew what it was called,” I say. I must’ve heard it a thousand times through the bathroom door when I was little. My mom used to play it on the shower CD player when she took her long baths, Jean Naté and Mr. Bubbles after days full of cancer-rattled collies or tending to her girlfriends Reena and Rae who had to take that second mortgage on their hair salon.

The music purrs and swells with such melancholy, and, half sick at heart already, I find myself swaying, caught up. Wanting to shut my eyes and sink into its sweet harbors.

Smiling at me, Serge holds out his hand.

I swear this happens: I rise, and for a brief moment, we are dancing. Just one, two, three twirls around before we stop, and Serge’s warm hand releases mine.

Diane is looking at us both and saying nothing.

“The tea,” Serge says, lifting a finger. “Just a moment.”

Maybe, I think, against all logic, everything will be okay. Maybe it will all work out. Serge likes me and he will understand and help us. And maybe Diane will pull herself together again.

“This is just like before,” she says, barely a whisper. “It’s the same as before.”

“Diane,” I say. “Are you okay?”

She must have fallen too, her head hitting the floor or wall. A hard knot is faintly visible beneath her smooth, wide forehead, the blood-brush framing it.

“This is what I used to listen to when I worked in a pathogen unit,” Serge says from the kitchenette. “We gassed hundreds of mice every day. I cleaned the container after each batch. The new ones can smell the pheromones. It is very distressing for them.”

I look at Diane, then back at Serge in the kitchenette, his head obscured by the open cabinets.

“It must be so hard,” I say, just to say something. “To do what you have to do.”

I remember the rumor about Serge’s sister. That she’d died of leukemia at age ten or twelve. His eyes blinking behind the kettle steam, he looks at me, and I can feel the music rise again, bittersweet, with each string pluck felt keenly and left vibrating through me.

“It is hard, in a way,” he says, returning with a tray holding an enamel teapot, mugs of smoked green glass, and a small jar of seedy red jam. “But if we do it, you do not have to.”

“My mom worked at an animal-rescue clinic,” I say. “I don’t think either of us ever got used to it.”

I don’t know why I’m talking this way. Why I’m pretending what’s going on isn’t really going on. The music, the strangeness of everything.

“Well, Kit,” he says, setting the tray on a makeshift table, a wastebasket he overturns, “you need to be more like Diane.”

We both look at Diane, who is staring at the tray, the steaming mugs, the bruised-looking jam.

“What?” I ask, thinking I misheard.

“Let’s just say,” he says, sitting, “she has a deeper view of life. I learned that years ago.”

“What do you mean?” I say. “When Diane interned with Dr. Severin?”

Serge smiles in that way of his, weary-eyed and vaguely charmed. I see him trying to meet her eyes. She will not surrender them to him or to me.

“You did not tell her?” Serge says to Diane, who lifts her head, her face now eerily calm, as if she has quickly stitched it together again from whatever antic state it was in.

“The internship, yes,” she says, talking to me but staring at Serge, lips moist, crossing her legs. “The summer between college and grad school—Serge was a junior lab tech.”

The music stops, the speaker clicking.

Serge dips a small spoon in the jam dish. “Fruit, yes?” he says, spoon hovering over our cups. “It is the Russian way.”

“Yes,” we both murmur at once, thoughtlessly. Polite. The way we’d long ago learned to be. Everything feels so strange that nothing does.

Steam dampening his face, he sets his cup down and leans back.

“I will not forget it,” he says. “One of the mothers needed to be put down, and all her babies too. Usually we have to send students home after. The first time, at least. Not Diane. She destroyed them all handily.”

I look at Diane, who is so very still. The knot in her forehead, though, seems to pulsate, as if flooded with blood.

“And then she sliced and diced them, as you say,” Serge continues, folding his long spider arms, crossing his long spider legs. “The best necropsist Dr. Severin ever had.”

My eyes dart between them both. I know I’m not understanding something, or anything, and the speaker keeps clicking.

“Look,” I say, “let’s all just—”

“It was the job,” Diane says, softly, barely audibly. “We’ve all done it. Countless times.” She turns to me. “Haven’t you?”

“Well, yes,” I say. “Yes. I mean, not that way, but…”

Serge leans forward, hand resting on top of the teapot.

“It was Diane’s job,” Serge says to me. “But I have never seen anyone do it with such composure. One might even say gusto. The only one who came close was a young man whose family was in the slaughterhouse business. But Diane. Her preferred method was decapitation with heavy scissors.”

Diane’s voice goes tight. “That was protocol for newborn mice. I was told they were less than seven days old.”

“I would have told you they were nearly twenty days old,” Serge says. “But you did not wish to wait. As we have seen.”

Diane shoves her hands in her pockets and turns in her chair, away from us.

“Whenever she finished the necropsy,” he says, “the skin removed, the organs, the head detached, she looked so…how do you say it? Afterglow?”

We all sit for a moment, Serge’s eyes dancing with something like pleasure.

“You wanted me to cry,” Diane whispers. “Like a girl. I should have cried.”

We can judge the heart of a man by his treatment of animals. That was what Serge told me the first time he watched me handling the mice. I am sure Mr. Kant meant the heart of a woman too.

Serge shakes his head. “A crocodile cries only because it has not eaten its prey.”

“What do you want?” Diane says. “Tell me what you want from me.”

The speaker clicks and “The Swan” returns.

“What do I want?” he says. “I want people like you banished from my world.” His voice is hard, relentless. “Those born with a splinter of ice in their hearts.”

Serge looks at her in that way he has, the same look he has when a postdoc hasn’t put on a gown before entering the vivarium or when he doesn’t separate the mouse litters. Under his invasive gaze, so sure of himself, so acute, Diane seems to shrink. It makes me feel sorry for her in a way I can’t explain.

“Is it money?” Diane says, softly now. “Is that what you’re looking for?”

“What makes you think there’s money enough in the world?” His eyes hot on her. “To make me unknow what I know? I saw what you did to that young man.”

What you did to that young man…

“Serge,” I call out, realizing it at last, “you’ve got it wrong. Diane didn’t do anything to Alex. It was an accident. I was there. He was running a flash column and there was a crack—”

But Serge is not listening to me.

“Diane, why did you have to involve her?” he says, flicking one finger, resting on a knee, toward me. “She doesn’t know what you are.”

“You don’t know what you’re talking about,” Diane murmurs, recrossing her legs, foot shaking now. Swinging like a metronome.

“I have done some investigations these past few days,” Serge says. “I have uncovered some questionable things. Your father, a heart attack at forty-two?”

No, Serge. Diane, white and waxy as a cake of soap, looks at him. Inside, I can feel everything falling apart.

“No history of cardiac trouble,” Serge continues. “No one asked for an autopsy. Tell me, was he your first?”

“Stop!” Diane pitches forward, her knee hitting the makeshift table, sending spoons to the floor and blobs of jam skittering. Hot tea splotching us all.

“I’ll get towels,” Serge says, rising, rushing to the kitchenette. And there I am, bending down to scoop spoons and jam from the floor. The veneer of civilization we cling to amid chaos and carnage.

“Diane,” I say, sitting up again, setting the spoons down, “please, just…”

Immediately, I know something is wrong. Her eyes are glistening strangely, like animals right when they go under or like my mom those last days at the hospital. My heart catches a moment.

Serge returns with tea towels. “What has happened?” he asks.

Because my eyes are on Diane, who now has one hand balled into a fist against her knee.

“Did the water burn your hand?” I ask, squinting.

“We’ll be here forever,” she whispers. “We have no place else to go.”

“Diane,” I say, eyes on her clamped fingers, red and insistent. “Diane, let me see your hand.”

But she’s looking at Serge and he’s looking at her. “Was he some kind of threat to you?” Serge says. “Do you just go around killing any man who gets in your way?”

“Diane,” I say. “What’s in your hand?” Because now I know something is.

She isn’t listening to me. No one is.

“I knew what you were, all those years ago. The way you handled those mice,” Serge is saying, fingers touching his neck, leaving pink spots. “I cannot abide it any longer. This is where it ends.”

“You think you know things about me?” Diane says finally. An odd dreamy tone, her balled hand opening and closing now. And I know I see something in it. “You think you know because of the way I euthanized those mice?”

Serge looks at both of us, touching his cheek with the palm of his hand. His face is newly pink, pink as a Pink Pearl eraser.

It comes to me in that instant, the thought, the panic.

This is just like before, Diane said, just a few moments ago. It’s the same as before.

“Don’t!” I say, reaching for Serge, knocking his teacup from his hand.

“What?” he says. “What?”

“Diane, what was it?” I say, grabbing her hand, her palm sticky and white.

Head wobbling, Serge reaches down and lifts the teacup to his face, under his nose.

“How did I miss it?” he asks, nearly smiling. “How did I not realize?”

“You shouldn’t have done this,” Diane says to Serge, her voice so delicate, vaguely mournful. “I’m so, so sorry you did this.”

He lifts one hand to his cheek, rests it there, as if puzzled by everything, by life. By the darkness unspooling at his feet.

“You killed me,” he says, a rattling gasp.

Those words, the very same words Alex spoke to me.

“You killed me.”

There’s a thin band of white at his hairline, but the rest of Serge’s face, his long graceful neck, has bloomed cherry red, redder than the jam, as red as poor Alex’s hot blood.

“Oh, Diane,” I wail.

But just as I reach out for him, Serge tumbles to the floor, his chin smacking the carpet, his arms and legs zigzagging. Froth hangs like lace from bluing lips.

Sinking to the floor, a blur of things: my hands on his curled-in chest, the sickly sound of his receding breaths, leaning over, my mouth open over his.

“Don’t,” Diane calls out. “Kit, don’t put your mouth on him!”

And I can smell it then, what’s inside him. Cyanide. The same scent drifting from his smoky teacup. Like an apple core gone to rot.

“Oh no,” I say. I say it over and over, reaching into my lab coat pocket for my phone, hoping it’s still there. But just as I shake it loose into my palm she slaps it from my hand, sending it careering across the room.

My arm flies up at her; the heel of my hand shoves her, knocking her back into her chair.

The sound from Serge’s mouth is terrible. The death rattle like in an old horror movie, but more plaintive, more lost.

I place my hand on his chest, which is utterly still, as I knew it would be. The heart so big, it burst. It’s almost as if a wave of cold passes from Serge over me and I know he’s gone. I know it.

“It’s just like before, and no more real,” Diane is saying. She looks like a frame of film paused, her body halfway between sitting and rising, her hands gripping the seat.

Then, looking at me: “Is this really happening, Kit?”

That’s when I see the shadow on the floor. Turning, peering up, I see her in the doorway, her face somber and full of woe.

“Oh, Diane,” Dr. Severin says, looking down at her, a look of infinite sadness, “what have you done?”