“Not ominous,” mutters Jacob. “Not ominous at all.”

“In the 1700s,” continues Dad, addressing Annette’s camera, “Paris had a problem. The dead outnumbered the living, and the living had no place to put them. The graveyards were overflowing, sometimes literally, and something had to be done. And so the conversion of the Catacombs began.”

“It would take two whole years,” says Mom, “to move the bodies of the dead. Imagine, a nightly procession of corpse-filled wagons rattling through the streets, as six million dead were ferried from their resting places into the tunnels beneath Paris.”

It’s so weird, watching them like this. The way they transform in front of the camera. They don’t become different people, they just become sharper, louder, more colorful. The same song with the volume turned up. Dad, the image of a scholar. Mom, the picture of a dreamer. Together, “the Inspecters” look larger than life. I snap a photo of them being filmed as Dad goes on.

“For decades,” he says, “the bones of the dead littered these tunnel floors, the remains piled haphazardly throughout the vast tomb. It wasn’t until an engineer by the name of Louis-étienne Héricart decided to convert the grave into a place for visitors that the real transformation began and the Empire of the Dead was formed.”

Mom gestures, like a showman pulling back a curtain. “Shall we go in?”

“I think I’ll wait here,” says Jacob, suddenly fascinated by the glass cases.

Suit yourself, I think.

I follow the crew forward without looking back. And even though I can’t hear Jacob’s steps, I know he’s there, on my heels, close as a shadow as we step through into a world of bones.

The bones are everywhere.

They line the dirt walls, a sea of skeletons rising almost to the ceiling. They form patterns, rippling designs—a wave of skulls set on a backdrop of femurs, the morbid decorations stacked as high as I can see. Empty eye sockets stare out, and jaws hang open. Some of the bones are broken, crumbling, and others look startlingly fresh. If you squint hard enough, the pieces disappear, and you’re left with a pattern of wavering grays that could be stone instead of bone.

Our shadows dance on the walls, and I take photo after photo, knowing the camera will only capture what’s here, only see the real. But right now, the real is strange enough. Strange, and chilling, and almost—beautiful.

“And horrifying,” says Jacob. “Don’t forget horrifying.”

We round a corner, and as if on cue, the EMF meter in Mom’s hand erupts from static into a high-pitched whine that echoes through the tunnels like a scream.

Mom jumps, and quickly switches the unit back off.

“Well,” she says, her voice a little shaky. “I think that says enough.”

I shiver, unsettled.

Even Pauline is looking tense.

“Gee, what could possibly be making her nervous?” muses Jacob. “Is it the fact we’re five stories underground? Or that this tunnel is roughly the size of a coffin? Or could it be the fact we’re surrounded by six million bodies?”

Six million—it’s a number so big it doesn’t seem real.

Two hundred and seventy—that’s a better number. Still a lot, but countable. Two hundred and seventy is the number of bones you have when you’re born. Some of them fuse together as you grow, so by the time you’re an adult, you have two hundred and six (thanks, Science class).

So, if the Catacombs are home to more than six million bodies, how many bones?

Six million times two hundred and six is—a lot. Too many to capture in a photo. But picture this: It’s enough bones to stack five feet high throughout every one of the tunnels under Paris. An Empire of the Dead as large as the city, the bodies unmarked and unknown.

Jacob begins to sing, and it takes me a solid thirty seconds to realize what he’s singing.

“… the foot bone’s connected to the leg bone, the leg bone’s connected to the knee bone …”

“Are you serious?” I whisper.

He throws up his hands. “Just trying to have a sense of humor about this.”

We wind our way through the tunnels, the locked iron gates converting the maze around us into a clear path. I wonder how easy it would be to get lost without those doors.

“Do you see this line overhead?” asks Dad, the question directed at the cameras as much as us.

I stare up and see a thick black mark painted on the ceiling.

“Back before they installed lights and gates, that was the only way to keep people from getting lost.”

I try to imagine coming down here before there was electricity, armed with just lanterns or candles. I shudder. The only thing that would make this place creepier would be being down here in the dark.

Mom turns to the camera.

“Over the years,” she says, “more than a few travelers have wandered down into these tunnels, to seek shelter, perhaps, or simply to explore, only to get lost amid the many halls. Many never found their way out again. At least, not while they were still alive.”

The Veil leans heavy on my shoulders, urging me to cross over, but I manage to hold my ground. I feel like I’m the glass box in my dream, the world pressing in from every side. But I don’t crack.

There’s no question Jacob is getting stronger.

But maybe I am, too.

“Over here,” calls Dad, his voice echoing. Here, here, here …

The bone walls are interrupted every so often by stone plaques, their surfaces carved with quotes about life and death. Dad stops in front of one, and Pauline and I hang back so our shadows don’t cross into the camera shot.

I glance sideways, and nearly jump out of my skin when a skull stares back, its empty sockets at eye level. Before I can think, I’m reaching out to touch the bleached white bone and—

All at once the Veil bristles, rising to my fingertips. As it does, I hear the muffled sound of voices beyond: sad, and lonely, and lost. Someone is calling out, and I can almost, almost hear the words. I lean closer.

“Hello?” calls a voice from the shadows, sounding scared.

I look around, but no one else seems to hear it. My parents walk on, and Pauline looks straight ahead.

“Cassidy,” hisses Jacob. “Don’t.”

My hand falls away, but I can still feel the Veil, sliding through my fingers like silk.

“… s’il vous pla?t …” comes another voice from the shadows, this one speaking French, the words thin and high and faint.

“… no one is coming …” murmurs a third. And then a fourth voice—

“HELP!”

The shout is so sudden and loud that I scramble backward. My heel catches a bit of rock on the ground and I stumble, unsteady. I reach out to catch myself, but this time, when my hand hits the wall, it keeps going, as if the surface is made of cloth instead of bone.

No, no, no, I think as the Veil parts beneath my fingers, and I fall down and through.

A short, sharp drop.

A shock of cold.

The taste of the river in my throat.

And then I’m on my hands and knees on the hard stone floor.

Pain scrapes across my palms, and my camera swings from the strap around my neck.

The tunnel is dark, and I blink my eyes rapidly, willing them to adjust. The only light I can see is the one coming from my own chest. The blue-white glow shines brightly, but only as far as my shirt. Not exactly a human flashlight. More like a human firefly.

I get to my feet, pulling the mirror from my back pocket.

“Jacob?” I whisper, but there’s no answer.

As my eyes adjust, I realize there’s another light, low and red, coming from around the corner. It reminds me of the light I use in my darkroom back home when I’m developing film.

I start toward it, and then I hear a small sound, like pebbles moving or feet shuffling over dirt, and the red light shrinks away.

“Hello?” I call, walking faster. But by the time I round the corner, the crimson light is gone, replaced by an old-fashioned lantern sitting on the ground. It throws off an unsteady yellow glow and casts shadows on the surrounding skulls, so it looks like they’re grinning. Scowling. Shocked.

I realize then how quiet the tunnel is, how empty.

I heard the ghosts, didn’t I? So where are they now?

Something moves behind me in the dark. I can feel it. My hand tightens on the pendant, and I’m working up the nerve to turn around when I hear the voice.

“Cassidy.”

Jacob. I sag with relief and I turn, only to find his face sharp, angry.

“I thought we agreed not to do this,” he says, arms folded tight across his chest.

“I didn’t want to,” I say. “I swear.”

“Whatever,” he says, “let’s just go before something—”

A pebble skitters across the stone floor behind us.

“Did you hear that?” I ask.

“Could be the bones settling,” he says, “or the wind.”

But there’s no wind down here, and we both know it wasn’t the bones, especially when the next sound is the crunch of feet. Someone else is here. I start forward, but Jacob catches my hand.