"A foot pr int ."

He takes another draw of snuff.

"Well, you know what they say about me, Poulain, I never forget a face. Or a footprint. Yours in particular. I checked my little file, just to be sure. Poulain, Arnaud. Size: bantam. Footprint: also bantam. Right boot bears telltale mark, crescent-shaped, from where hobnails have come out."

Poulain folds his arms across his bird chest.

"Boots lose their nails," he says.

"They do."

"Footprints get washed away."

"They do. Yes, this one would have been washed away if I hadn't scooped it up. Every last bit of it. Why, a few hours in my office, it was hard as plaster."

Tickling his arm into the turnip bag, Vidocq draws out a square of black clay, rimmed with straw . . . stamped with a single boot, like the fossil of an ancient fish.

"Now," he says, all air and light. "If you'd be so good as to take your boot off."

In the end, Poulain is like the ruffians at Denoyes'. When commanded, he obeys. He can't see any other road.

"Ah, you see," says Vidocq, placing the boot in the clay impress. "Fits like a corset. And look, see there? The crescent-the exact shape. Yes, my friend, I believe we have a match."

Not a trace of smugness in him, I will give him that. He has the air of a church artisan admiring someone else's transept.

"The boot never lies, my friend. But then it never needs to. Put it back on, there's a good fellow. No, wait. Allow me to tie."

In a single swift motion, he laces Poulain's boot to the chair leg.

"No offense, my friend. It's just a little precaution we take. But you're still looking a bit pale. Hey, Mama Maltaise! Another carafe for my friend here ! "

How slowly he pours this time around. As if the wine were the accretion of a single thought.

"Poulain," he says, pushing the glass gently toward him, "you're many things-believe me, I know all the things you are-but not a killer. Not yet."

Cupping his hand under Poulain's chin, he leans into him, eyes blazing.

"Tell us how it went," he whispers. "And maybe old Vidocq can find something in his bag of mercy, eh?"

From somewhere in the dark recesses, I hear the Widow Maltaise's cat, luxuriously bathing its paws.

"I was lucky," says Poulain. "That's all."

"How do you mean ? "

"I mean I just happened to be there. Minding my own business, if you must know. Helping myself to a muffin cart."

"Your own, of course."

Poulain's eyes squeeze even tighter. "I believe it was left behind by someone."

"Go on."

"And then I heard some noises, all right? In the alley off Rue des Macons."

"What sort of noises?"

"Oh, it was-I don't know-shit-being-knocked-about noises. I thought I'd have a look, in case there was action."

"And that's where you first saw Leblanc."

After careful consideration, he gives a nod.

"What was he doing?" Vidocq asks.

"Getting his stuffing taken out."