Soon my cell rings. A video call.

It’s Lara. She’s doesn’t bother with small talk. “Have you seen the news?”

“Hold on.” I find the remote and click the TV on. A news anchor talks briskly, a video playing above her shoulder. On that smaller screen, emergency lights flare atop a car.

It’s all in French, of course, but the message is painfully clear.

“Oh.”

On the TV, the news anchor cuts away to a woman sitting on the sidewalk while a medic presses a cloth to the side of her head. In the background, a multi-car collision clogs an intersection. I change the channel and see a map of the Metro covered in red outage markers.

I mute the TV, and Lara sits forward in her chair. “I warned you this would happen. Poltergeists are—” She stops abruptly, frowns. “Cassidy,” she says tightly, “who is that?”

I glance over my shoulder and see Adele perched on the arm of the sofa, Grim a mound of fur on her lap. “Oh yeah. That’s Adele.”

Adele tugs the lollipop out of her mouth and waves cheerfully. “Hello!”

Lara does not wave back.

“Are you a ghost hunter, too?” asks Adele.

At that, Lara goes very still, her dark eyes furious. “Cassidy Blake,” she hisses through clenched teeth. “What have you told her?”

“Not much,” I answer, at the same time Adele says, “Everything!”

Lara’s expression shifts from anger to horror. “Why would you do that?”

“I have to say,” muses Jacob, “it’s so nice to see that anger directed at someone else.”

“Be quiet, ghost,” she growls. “Cassidy, explain.”

“It just kind of came up,” I say.

“Oh yes, because spectral abilities are such a natural topic of conversation.”

“Look,” I explain. “I went to see Richard Laurent’s granddaughter, Sylvaine, but she wouldn’t talk to me. Adele’s her daughter. She tracked me down and brought me photographs—”

“Wait,” cuts in Lara. “What photographs?”

I turn the phone so she can see the pictures spread on the floor.

“Closer,” says Lara, and I crouch, panning the phone over them. Adele drops down cross-legged beside them. She reaches for a picture with only Thomas, looking back over his shoulder and flashing a wide smile.

“And you’re still no closer?” asks Lara. “To finding out what—”

“Such a sad story,” murmurs Adele, “what happened to Thomas.”

The room goes quiet. Jacob and I both stare. Even Lara’s mouth is hanging open on the screen.

“You know?” we all say at once.

Adele shifts a little. “Oui,” she says. “Maman told me. She doesn’t like to talk about the past, not with strangers, but she said it is important to know one’s history. She said it is private. But if it will help you help Thomas,” she adds, “I will tell you the story.”

It is a very sad story,” begins Adele, drawing Grim into her lap.

“My great-grandfather Richard was ten when it happened. He was three years older than Thomas, and he was Thomas’s hero. They were close. Like this—” She crosses her fingers. “Thomas used to follow Richard around. And Richard let him. All summer,” she continues, “Richard and a few other boys had been sneaking down into the Catacombs at night.”

“How?” asks Lara.

Adele shrugs. “Now there is only one entrance and one exit, but there used to be more. If you knew how to look for them. Richard did.” Adele flashes a small, mischievous smile. “So they would sneak down in the dark.”

Jacob and I both shudder a little at the thought of the Catacombs at night. The tunnel of bones lit only by candles or flashlights, some pale illumination that leaves the skeletons buried in shadow.

“And Thomas wanted to go, too. He begged and begged until one night, Richard finally agreed to take him.”

I glance at Jacob as Adele talks. His face is clouded, all the expression gone, as if his mind has wandered off while listening. But he must feel me looking because he blinks and cuts his gaze toward me, one eyebrow raised.

“And so they went,” continues Adele, stroking Grim. “Thomas, Richard, and two of Richard’s friends. Down into the dark.”

The cat is a puddle of black fur in her lap, the happiest I’ve seen him since getting to Paris. Adele must have a gift for befriending cranky cats.

“The boys were always playing games, and so that is what they did. They played cache-cache. Do you know what that is?”

I shake my head.

“You call it hide-and-seek.”

I jerk upright. “The counting!” I say, and Lara nods on the screen.

“Quoi?” asks Adele, looking between us. “What?”

“Un, deux, trois, quatre, cinq …” recites Lara in her flawless French. “I couldn’t understand why he’d be going up instead of down.”

“But if they were playing hide-and-seek,” I say, “and he was the seeker …”

Adele nods eagerly. “Thomas was too small, too good at hiding,” she says, “so they made him search instead. He closed his eyes to count, and the other boys all ran and hid.”

I imagine playing such a game down there, hiding, pressed against skeletons or climbing over bones, and I shudder.

“Thomas was very good at finding the other boys, no matter where they hid,” Adele goes on. “So on the third game, Richard agreed to let his little brother hide.”

My stomach twists as I realize where this is going.

“Richard was the seeker,” says Adele, “and he found one of his friends, and then the other, but no Thomas. Richard searched for almost an hour, before he finally gave up. The boys were tired. They wanted to go home. So Richard called out, ‘Thomas, c’est finit’—‘it’s over’—but there was no answer, except for his own voice, echoing in the tunnels.”

A shiver runs through me. If it were any other story, I might delight in the nervous thrill. But I have seen this small boy in his dirt-scuffed clothes. And I can picture him lost down there, hidden among the bones or wandering the tunnels, turned around, alone.

Adele goes on. “Richard stayed down there all night, searching for his brother. But he couldn’t find him. Finally, he had no choice. He went home and told his parents, who called the police, and they organized a search.”

I swallow hard. “Did they find Thomas? Eventually?”

Adele nods. “They did,” she says slowly. “But by then it was too late. He was already …” She trails off.

My chest tightens around the next question. “Where did they find him?”

Adele hesitates, petting Grim. “He was very good at hiding. He had climbed into one of the little …” She hesitates, searching for the word, then makes an arch with her hand. “Coin.”

“Nook,” translates Lara. “Like an alcove.”

Adele nods. “Oui. That. Anyway, he climbed in, nice and small. But the bones around him were old, and sometimes …” She makes a small, collapsing motion with her hands. “They slip. Sections fall.”