We stick to the houses and dart down the rue de la Joaillerie, circling the Châtelet on the right, heading toward the source of the smell: the numerous slaughterhouses that give the city’s butchers their meat and the Châtelet its sour perfume of rot and old blood.

“Another watches here,” I command. The Ghosts nod in perfect submission. They’re good at taking orders, and I watch them melt into the darkness with satisfaction. I’m light-headed and dizzy with anticipation. Can I do this? I glance at Ettie. She’s curled herself into a dark corner. If I don’t try, he’ll take her.

I disappear into the shadows with Ettie and the two remaining Ghosts.

Somewhere in the distance there’s the low hoot of an owl—a Master Call. I plaster myself to a nearby wall, flattening Ettie next to me, my hand over her mouth.

Two police officers appear. One holds a lantern and is walking a little ahead of the other. From the cut of his uniform and the absence of badges, it’s clear he’s accompanying a senior officer, whose dazzling array of badges and trim betrays his inspector’s rank. They must be heading to the gendarmerie.

I squint. The inspector cuts a slim figure. Most officers on a dark street would march quickly, not wanting to look into the darkness for fear of what might be looking back. But this officer walks with a measured step, his eyes taking in every shadow. He comes right alongside us, and in the halo of the lantern, I see that “he” is in fact a woman. Her face is white in the lamplight, her red hair tied behind her neck into a long tail. Policewomen are rare. Only the Sûreté have them. And the Sûreté are never good news.

She moves on. I watch in silence till she has disappeared from view.

I count to ten, then call the nearest Ghosts with a low whistle. I cross the street. Around the back of the Châtelet is a smaller edifice. There are no lights or guards, yet it is one of the most popular sights in Paris. By day, rich and poor alike line up for hours to press greasy faces against the glass of its window in the hopes of a better look. At night, nobody keeps watch over the contents because no one would steal from this place.

“I need two of you to carry,” I say.

Their eyes travel from me to the dark entrance.

“For your Father,” I add, and make short work of the two meager locks on the door.

Another time I’d have let Ettie practice her lock-picking. But the sight of the inspector spooked me. I want to be done with this. We push the door open and face the stench of decaying flesh. I breathe through my mouth. Beside me, Ettie hastily lifts her scarf over her nose and tries not to gag. I should have warned her.

The building is one giant room with a grimy storefront window. The whole space is filled with long wooden tables arranged with as little room between them as possible. They have raised edges so that their contents don’t slip off, and they are tilted so the Lookers can get a better look. Laid out on each table is a body.