“I’m sorry,” Julia says.

“Rather mugging than mitosis,” Genevieve says, and the joke is so unexpectedly dark that Julia smiles her first genuine smile of the evening.

“Sorry I made you think about him,” Julia says. Meaning: the man who mugged you, but also: the man you murdered.

Genevieve’s eyes flash. “Do you know,” she says. “I think about him all the time.”

“Do you?” Julia says, but it must be too much, too soon, because Genevieve turns away from her sharply.

Later, Julia knows, these emotions will come out in an explosion, some small perceived injustice or other.

“Sorry to be a party pooper, but I’m knackered,” Genevieve says, her back still to Julia. “Fill me in tomorrow? On the misper?”

“For sure,” Julia says, though she doesn’t mean it. She doesn’t understand the psychology, exactly, of Genevieve’s increasing interest in the crimes Julia investigates. Only that sheismore interested, since the mugging, almost obsessively so.

“Shimmyshaker,” Genevieve says, leaving the kitchen before Julia can raise it, and waving a hand above her head without turning around. An ancient greeting and goodbye, from a TV show she watched for hours and hours when she was little and Julia was trying to buy peace.The Fimbles—they’dwatched repeats on YouTube when it was taken off air, that’s how much they’d loved it. Their word stuck, in that way things in families sometimes do.

“Shimmyshaker,” Julia immediately says too, but her voice sounds weak and sad.

Art appears at the top of the stairs just as Genevieve begins to ascend them. The atmosphere immediately changes. Julia looks up at him and, as she has always felt when she sees her husband, time seems to stop for just a second or two.

Genevieve brushes past him. Their relationship appears unscathed after Art’s infidelity. Julia sometimes wonders if it is because he doesn’t know what Genevieve did. She is allowed to forget it, around him. And that is too precious to spoil with judgment over an affair.

“All right,” Art says calmly, walking toward Julia. As usual, his hair and clothes are all over the place. He just can’t look neat, even if he tries.

Julia moves into the kitchen, busying herself. She listens to her daughter upstairs, lights flicking on, doors opening and closing. She canfeelArt in the living room, even though she can’t hear or see him. She thinks, as she often does, about the colleague he slept with. Elle. Julia couldn’t believe it when he told her—two days after the first confession—who it had been. They had known her well. Dinners, one New Year’s Eve spent together. But Julia had never trusted her. And rightly so.

She couldn’t believe, either, that it was coincidence, that Art hadn’t always intended to sleep with her eventually. Julia would see their text exchanges. “I know, right?” Elle would have messaged Art. “Total week seven vibes.” “What’s week seven?” Julia would say—Art was never secretive with his phone. “Long story—inside joke,” he’d say.

Afterward, Elle had left the school where they both worked. Art said he’d deleted her number, like that was that.

She wipes a kitchen counter for something to do—Julia has done more performance cleaning in the past four months than ever before—then straightens up the oven gloves, folded over the handle of the oven door.

She stops and stands there, alone, and that is when the enormity of what has happened to her descends, like she’s opened a shaft to hell. She leans her elbows on the counter, breathing deeply. Jesus Christ. She doesn’t deserve this. At every turn of her life, she’s tried to do what a good mother and a good police officer would do—hasn’t she? But, today, the two compete. Art is the only person on the planet who would understand, but she can’t tell him. It’s too late. In giving him her secret, she would be making a trade, she knows it. Confiding in somebody who has already taken her trust, and broken it.

She shakes her head, trying to keep it together, the keening terror, the shame, trying to think. After a couple of minutes, she straightens up, as though nothing has happened at all, and gathers the things she needs. The things she needs to find the man in the balaclava. To work out how he knows what he knows, to disarm him of that evidence.

She walks past Art, eventually, her body language stiff and awkward, and upstairs to the bedroom that she sleeps in alone. As soon as she enters, she thinks the same thing she thinks every fucking evening: about their old ritual, from the days before. There was a skylight over the bed in their old house, and they used to leave the blind open, look at the stars, debrief before sleep. Julia would tell Art her worries, and he would take them from her. Now, in the new house, there’s no skylight, and there’s no intimacy, either.

She hears him coming upstairs. “Night,” he says to her,a word thrown out into the ether. She doesn’t reply, even though he’s one of the only people who would understand what she did for Genevieve, who would understand the dilemma she faces. But she can’t. It’s too late.

She can hear the sea beyond the windows. The tide’s out. It ruffles like a taffeta dress. In and out, in and out, a ballroom dancer of an ocean.

She heads into the bathroom and finds the nail clippers. First, she rubs them over with alcohol hand gel she brought up from the kitchen. Next, she uses the tool to scrape, very carefully, under the nail she scratched her assailant with. She puts the scrapings into a tiny Tupperware pot she also brought up with her.

She’s no good at forensics, but she must know more than most, and this might be enough, she thinks, descending the stairs to put the pot in the fridge. She holds it up to the light, then places it at the back, among the open pesto jars and bell peppers, like some science specimen. A small white curl of skin fibers, his and hers.

In bed, she puts on the reading glasses that she’s only begun to need recently. The analysts will be going through Olivia’s vast online presence, but Julia starts now, too. She’ll read alongside them.

Because that is the only thing that will truly, truly help: finding Olivia. If she finds Olivia alive, the problem goes away. If she finds her dead, she can investigate her murder.

Art comes out of his room and goes into the bathroom. “Don’thog it,” Genevieve shouts. And there it is: her explosion. Offense is her greatest defense, maybe. Art thinks it’s teenage hormones.

“Shall I just use a bucket outside?” he suggests.

“I need to put my retinoids on,” Genevieve says.

“They sound like a disease.”