I saw it. This is what Diane could say to the detectives. I walked into the lab and saw it with my own eyes. Kit killed Alex. Three days ago, in this very lab.

If she wanted to save herself, she could say that. It’d be a risky move, given what I could say about her, but who could know what drove Diane?

Didn’t you know? Diane could say. They were involved. Alex and Kit. They had, recently, been intimate.

I could imagine the whole thing.

I don’t know why Kit did it. Maybe she found out about the girlfriend. The fiancée. Because she certainly didn’t know before.

Women are complicated creatures, after all. All those hormones raging inside. And with women, isn’t it always a crime of passion?

Kit’s always been a passionate person.

I saw it. This is what I, in turn, could say to the detectives. I walked into the lab and saw it with my own eyes. Diane killed Alex.

Didn’t you know? I could say. He found out about her past. About how Diane killed her own father.

A crime of passion. Diane’s always been a passionate person. Most women are.

I could say all these things. And she knows it.

Diane and me, partners in crime. A Mexican standoff, both our guns poised, ready for the head shot if we must.

When it’s my turn, I tell myself, I will be ready.

Back in G-21, Zell and Maxim are packing up glassware while two of Irwin’s postdocs—matching wire-rims, khakis one infinitesimal shade apart—supervise, clipboards in hand. Juwon is with the detectives.

“They’re moving you to Irwin’s already?” I say.

Zell rises from his crouch over the box, stuffing the top of his errant boxer shorts back into the waistband of his jeans.

“Herr Severin doesn’t waste time.”

“Don’t you mean Frau?” one of the Irwins says, grinning.

“No,” Zell says, not looking at him, “I don’t.” He seems more subdued by the hour, as if yesterday’s disappointment is finally sinking in.

“The blonde was looking for you,” Zell says.

“The blonde?” I walk toward my bench. “Diane?”

“No, the civilian. The fiancée. She seemed like she really, really needed to see you.”

Zell faces me, cocking his head. There’s a mean look in his eyes.

“Okay, thanks,” I say, not moving.

I had no idea until today just how much he dislikes me. And there he is, standing just a few feet from where Alex stood. I look right back at him, at his doughy skin, his ruddy throat, uncut. I do not blink.

For a second, watching my expression, he seems to shrink from me.

Maxim covers a beaker in bubble wrap and says nothing, but his eyes are on me also. And Irwin’s men. They’re looking too.

“Congratulations, by the way,” one of Irwin’s postdocs says to me. “Cheers to you and all that.”

All four of them looking at me like I just ate their cherry pie.

I’m the very last one called down the hall. I’ve watched as Juwon, Maxim, Zell slipped in and out of those doors. I’ve imagined every self-serving or insinuating thing they might say.

But worse still is what Diane might have said.

It’s strange to be in Dr. Severin’s office without Dr. Severin. Strange to see a police detective, holster on, sitting in that high-backed leather chair.

Detective Harper is petite, small-boned, neck like a baby starling’s. Still, she looks strong, arms folded across her blue shirt. Shoulders squared. And her hands are big for her size, nails cut to the quick. Her black hair is smoothed flat and pulled back with combs like a Spanish dancer’s. When she turns I can see the pins crisscrossed in the braided bun.

I bet it takes her a long time each night to untangle those braids, to pull free all the combs and pins put in place for her job, her world, another world of men. I picture her standing at the mirror, dropping them into the sink. I wonder who she takes her hair down for. Or is it just for herself?

Every morning for the past decade I’ve dragged my hair—what color even is it? The color of spring mud, like all the Owenses’, my cousin Scott once said—into a ponytail. It gets in the way even like that, strands sliding loose, the humming ventilators blowing on me all day. You can’t really use hairspray in the lab, unless you want to set your head on fire.

It would be easier to cut it all off. Maybe that’s why Diane did it.

I’ve always kept mine long, though I’ve forgotten why.

You, Alex said that night after Zipperz, his fingers sliding under the elastic, pressing into my scalp, your hair smells just like you.

Solvent? Cell cultures? I’d laughed, the ends tickling me, slipping into the hollow of my throat.

Like a match, he’d said, just lit.

“So,” Detective Harper says, “you’ve known Alex Shaffer how long?”

“A few months. Since he started here.”

“You work together?”

I shift in my chair, so close to the window, the sun’s glare in my eyes. “We all work together.”

She looks at me and blinks once. “So that’s a yes?”

“Yes.” I curl my fingers under. Keep it simple, I tell myself.

“And you say the last time you saw him was here three days ago? That’s Saturday?”

“That’s right. Well, down the hall. In the lab.”

“He was working?”

“Yes.”

“Was that typical? On a weekend morning, so early?”

“Not that typical, no.”

“Was he behind on work?”

“Maybe. I don’t know. I focus on my own work.”

“So what kind of guy is he?”

“Nice. Easygoing.”

“Smart?”

“Of course. I mean, yes.”

“You’re all smart,” she says, a hint of a smile lurking there.

“Yes,” I say, matching her gaze. “We are.”

And so it goes. What was he wearing? What was his mood? Did you notice anything unusual about his behavior?

We circle around and around and around as I try not to stare at the detective’s small spiral notebook on the desk, a pen tucked inside. Each time, I give the briefest of answers—I don’t know, jeans, a shirt. Fine. Nothing unusual, no—my eyes fixed on Dr. Severin’s desk, a thunk of wood that looks like barn boards. That framed picture to the right, the one I always assume is Severin herself when she was young, a little pigtailed girl in a cowboy hat, fried rattlesnake in her stubby hands, her grim, flat-line mouth. Dr. Severin, a once and forever cowboy, frontierswoman, pioneer in pursuit of her destiny, the research she was born to do.

It’s one thing to be smart, brilliant even, but something else to be able to do all that Severin does. Always in motion, eyes on the horizon, wrangling all her cattle, all her work oxen and beef makers and errant postdocs, branding them, driving them long across hard country, never losing sight of something she sees even if no one else sees it.

If she came to believe that one of us might hold her back, bring her down, what would she do? What would it take for her to cut one of those steers loose? If she saw one go slack, turn lame, froth rabid, would she send it to the killing floor?

“And you said you left around nine with Diane Fleming?”

“Yes.”

“Did you see anyone else here?

“Just Serge. Like I said.”

She looks down at a piece of paper in her hand. “You exchanged greetings—you, Diane, Serge. That was it?”

“That was it.” I don’t say anything about the biohazard bag. She does not ask.

“What kind of guy is Serge?”

“Serge?” I say. “He’s an animal guy, you know. Very dedicated, very protective.”

“Protective?”

“He’s great at his job. That’s what I mean.”

She taps her pen on the pad. “Does Alex think he’s great?”

I look up, surprised. “I don’t know.” I have only a second to decide, or at least that’s how it feels. “Serge thinks Alex is …messy.”

Her right eyebrow lifts. “Messy how?”

“Just not careful with his equipment. Not clean. Serge is particular. A lot of techs are.” Has someone, I think, said something about Serge? Has Diane?

She looks at me. “Are you friends?”

“With Serge?” I say. “We’re friendly. The postdocs—we don’t really hang out with the techs.”

“Got it,” she says. “Caste systems all over, right?”

I look at her. “No,” I say. “The vivarium is in another part of the building. That’s all I mean.”

She looks at me, nodding slowly. “Sure.”

I begin to think it’s nearly over. It’s nearly over and Diane must have not said anything to cast suspicion on me. Why would she? I remind myself. Everything is fine.

“One last thing,” she says. And I ready myself for the old Columbo move, another of my dad’s favorites. “You and Alex Shaffer, you socialize much?”

“Sorry?” I say. “Socialize?”

She pauses, studying me, or so it seems.

“Do you eat lunch together?” the detective asks. “Does he bring you coffee?”

“Who told you that?” I ask. Immediately, I want to roll the words back into my mouth.

She squints at me. “Is the light bothering you?”

“No,” I say. “Coffee. Sure, yeah. We all drink a lot of coffee.”

“Maybe go out for drinks?”

“Drinks?” I wonder how long I can keep repeating her questions back to her.

What did she tell them? I think.

“After a long workday,” the detective says, leaning back, adjusting the blinds on the window behind her. “Happy hour, five-dollar pitchers, free wings, that kind of thing.”

“We work pretty late.”

“So is that a yes or a no?”

Breathe, breathe. “A few times.”

“When was the last time?”

“I don’t know,” I say, trying not to stutter. “Last week, the week before.”

She narrows her eyes.

Diane, Diane, Diane, how dare you.

“We work a lot, Detective,” I say, as evenly as I can. “The days can blur together.”

“And when was the last time you heard from Alex?”

I look up. “I told you. I—we saw him here on Saturday morning. Just for a few minutes, but he was working.”

“Right. But you two texted occasionally, right?”

“Sometimes,” I say, the sick feeling returning.

“How often?”

“Sometimes,” I say again, my hand on my phone in my pocket. “We all do.”

“So have you gotten any texts from him since seeing him on Saturday?”

“No,” I say, truthfully.

“Did he talk much about his home life?”

“No. None of us do. We’re here a lot.”

“Were you friendly with his fiancée?” she asks.

“No,” I say, pinching my fingers against the sides of my chair. “I’m sorry. What does this have to do with Alex being missing?”

“Not at work parties, that sort of thing?” she asks, not answering my question.

In my head, I am picturing Diane: Kit didn’t even know he had a girlfriend. They had a flirtation. Well, a little more than a flirtation—

“No, I’d never met her. Not until—you know.”

“Did he talk about her, about getting married?”

“No,” I say.

I’m looking at the blinds instead of her face.

“Have you two ever been romantically involved?” she finally asks. She asks it lightly, flicking her eyes up to watch my reaction.

There it is. Diane. It can only be Diane.

“No,” I say. “We have not.”

She looks at me very closely. I can see a small vein at her hairline. A wiggly wormy little vein that I think is her tell. I just don’t know what she’s telling.

“Okay,” she says.

“Did someone say that?” I ask.

“We’re looking into all the possibilities,” she says. “Sometimes, if there’s trouble at home, it can feel like a lot of pressure. Maybe they leave town for a while.”

“Maybe,” I say. “Maybe some people do.”

She smiles. “Some men. Runaway grooms.”

I look at her, the echo of Dr. Severin’s phrase humming back at me.

“Maybe,” I say, and trying to recover, trying to be light, I shrug. Then, remembering something my dad used to say in his spooky nighttime voice, I add, “Who knows what evil lurks in the hearts of men?”

Harper smiles again, laughs even.

“We’re done?”

“That’s all for right now,” she says, closing her notebook, her eyes drifting to the press release about the PMDD study on the desk. “So you’re an investigator too,” she says.

“In a way,” I say. “I mean, yes. We’re trying to solve a different kind of mystery.”

She grins. “So let me ask you: Where do you think Alex Shaffer is? What’s your hypothesis, Miss Owens?”

I look at her, thinking.

“Sorry.” She corrects herself. “Dr. Owens.”

“I don’t know where he is,” I say. “Hopefully not far.” I rise, smoothing my lab coat. I am careful. I say it just right. “He’s one of us, after all.”

Is, is, is one of us. After all.

Ilene glances up at me from her desk as I leave Dr. Severin’s office. Lips pursed, she jiggles her computer mouse and says nothing.

But when I move past her, I can feel her eyes on me. Dark and narrow, like little arrows.

Shoving my hands into my lab-coat pockets, I begin walking. My fingers touch fur, and for a second I start. One of Serge’s mice?

But no, of course, it’s Diane’s rabbit’s foot, too late to bring me luck. Or just in time to bring me something else.

I walk the hallways for ten, fifteen minutes looking for her. I’m afraid to call or text, afraid to use my phone, so I move to the large windows at the front of the building and perch on the sill. Waiting.

Why would Diane point a finger at me when she’s the one who helped me to begin with? Accomplices in a cover-up. This is what I’m wondering, my head heavy and throbbing.

If it weren’t for her, I’d have called 911, I’d have rung for campus security.

Unless, I think, something heavy sinking inside me, pulling me down, that was her plan all along.

Some people, Serge had said, are very focused on themselves.

Did she stop me from calling, did she push me into this byzantine cover-up not to protect me but to put a target on my back?

These had been fighting, Serge had said, looking into the mice cage, so we removed the dominant one. It will be better, don’t you think?

When she came to my apartment that first night, when she told me I was on the PMDD team, I’d reminded her over and over again what she’d done, what she was.

Did she decide to get rid of me when she saw she had a chance? The last viper in the vipers’ nest. Look at you, she’d said in G-21, Alex’s body on the floor. What do you think the police will decide the minute they see you? Convincing me not to call 911. Convincing me to join a cover-up. Making me look guiltier and guiltier.

Why, I think now, and it’s like a blow to the chest, would you keep around the only person who knows who you really are? What you really are.

The staircase door beside me swings open, a cloud of smoke emerging.

Dr. Severin appears behind it, hand to her mouth, wiping a stray bit of tobacco from her lip.

“Kit,” she says. I can’t remember her saying my first name before. “How did it go?”

“Pardon?” I say with a start.

“With the police.” From her lab-coat pocket, she takes out a makeup mirror, a silver clamshell burnished like a sheriff’s star, and opens it.

I clear my throat. “Fine. I mean, I wish I could have been more helpful.”

“I’m sure you were just as helpful as you needed to be,” she says, clicking the mirror shut. “We must keep our focus on the work. That’s what’s gotten us this far.”

I can’t stop myself.

“You and Diane?” I say. “You go so far back.” There is something in this. The fact that neither of them told me, mentioned it at all.

She pauses, then sighs, stepping closer to me, very close.

“Is this workplace paranoia?” she asks. “Or is it impostor syndrome? That is the real female malady. Perhaps we should be studying that.”

I can smell the cigarettes on her for the first time. We are that close.

“You’re smarter than this, Kit,” she says, her hand on my arm for a fleeting second. “I’m the only one in the world who knows just how smart you are.”

It means something to me to hear this from her. I think she’s probably right.

Down the hall, Ilene appears, looks at Dr. Severin, and points at her watch.

“That goddamn dean’s champagne toast,” Severin mutters.

“I’ll be there,” I say.

“You will,” Dr. Severin says, turning away. Waving good-bye over her shoulder.

I watch her walk down the hall, the long dark skirt like an exclamation point.

Though we’re both heading in the same direction, I wait. Catch my breath.

“We’re lucky, our kind, if we get one shot,” she’s saying as she walks away. “Even one. We may only get one.”

What would it take for her to decide one of her team members was more of a liability than an asset? What might Diane have told her?

You would think that in a lab, with its key cards and protocols, its hazardous materials and rules, the walls would be thicker. But the lab is old, dropped ceilings that sag and bellow, belching steam heat, furring pipes, rodent-gnawed spray foam. A lab is supposed to be sleek, immaculate. A building-size brain whirring with activity. Not a place for human sounds, the quivers of the heart.

And so, when I hear the noise coming from the lounge, I feel a fumble in my chest.

“What is that?” I ask Maxim. Cleaning his bench methodically and grievously for the last time. The act for him is sorrowful and wrong. Zell just took one arm and swept everything on his bench into a mail bin.

“It’s the fiancée,” Maxim says, looking up as the bleat returns. “The lament of the fiancée.”

It sounds like she’s talking on the phone and crying.

No one’s ever cried in the lab before—not in front of anyone, anyway. Once, after a trying day and the awful realization that I’d lost three weeks’ work to mysteriously contaminated cultures, I’d hidden in a stall in the bathroom and flushed the toilet four times to conceal my crying. With only a handful of women in the whole building, who would have heard me? But I didn’t want to hear myself.

Zell’s fiddling with his phone. “Isn’t she looking for you?”

I need to talk to Diane. I need to find out what she’s done. But Eleanor finds me first, opening the door from the lounge just as I try to pass, hurriedly.

“There you are,” she says. Her hair is lank, a forlorn banana peel, and her face, pink and tender. But her jaw is set and there’s a new coldness in her voice.

“I’m sorry,” I say, “but I’m late already. We have to be in the auditorium for the—”

But she pulls me into the lounge. There is no stopping her.

“I think something bad’s happened to Alex,” she says, her hands wrapped around each other, a diamond poking angrily between her fingers.

“No,” I say firmly. “Look, it’s only been a few days. It—”

“I was just telling his parents. The police pinged Alex’s phone,” she says. “It’s either turned off or the battery ran out. This is the last known location.”

“The lab?”

“Or nearby.”

“Cell towers,” I say, as dismissively as I can, trying not to ponder what they can find out next. Texts between Alex and me? I’ve been thinking a lot about it and I have to tell Dr. Severin. Alex, you CANNOT do this. “That’s junk science. It doesn’t mean anything.” I pause. “I don’t have to tell you that.”

But she will not be stopped.

“There’s something else,” she says, blocking me as I try to pass, leaning against the hard casement corner into the next wing. “Thursday night, I was supposed to see Alex, but he never called me back. And when I talked to him Friday, he said he forgot, but now the detectives keep asking about it.”

Thursday night.

“You know cops,” I say, averting my eyes, fighting off a vaulting panic.

“We had plans, a lecture I wanted to go to. I drove by his apartment a few times.” She looks at me, jaw tight. “I don’t think he ever came home.”

Zipperz Thursday-night specials. Long Island Iced Teas, two for one.

She looks at me, head tilted. “Did you see him Thursday night? Were you all working late or something?”

I move to the door. “No. Sorry. I left early.”

She doesn’t say anything, her mouth opening then closing.

“I’m sure it’s nothing,” I add.

“Why are you so sure?” she asks after a moment. The chilliness chillier.

I glance at the clock on the wall. Two fifty-seven, thank God.

“Eleanor, I’m sorry. I have to go,” I say, not quite pushing past her. “It’s later than I thought.”