"Duty calls," says Father, gulping down the last of his coffee. Reaching for his greatcoat and bag, he kisses her in the usual manner: three quick collisions of lip.

"Off to the hospital," he adds.

And with that tiny superf luity, he once again betrays himself. Why would a man announce he's going to the place he goes every morning? Unless he's not really going there?

"Good-bye," she hears herself say.

She's about to turn away when she notices he hasn't quite closed the door after him. She puts her hand to the knob-and to her surprise, finds that her hand won't budge. For several long seconds, she interrogates it. Then she calls out to Clothilde:

"I've just remembered. Monsieur Beaucaire wants me to pick up that brooch. My mother's old brooch? The one that had to be recast? It's only a few blocks, I should be back within the half hour. No more than an hour . . ."

It pains her to admit that she's every bit as bad at lying as her husband. She kisses me on the forehead. She announces (again!) that she'll be back within the hour. On her way out, she reaches for a shawl. Not because the morning is cool but because she has already begun to see the wisdom of concealing herself.

And as she follows that familiar greatcoated figure down the Rue Neuve-Sainte-Genevieve, she finds herself, without any prompting from Vidocq, observing the principles of surveillance: keeping a safe distance from the quarry, avoiding direct eye contact, rearranging her appearance. So many precautions, and none of them needed. After many months, Dr. Carpentier has ceased to care if anyone is following.

She tracks him up the Vieille Estrapade, down the Rue d'Ulm, right on the Rue des Ursulines . . . and then, at the corner of the Rue SaintJacques, she watches in dismay as he hails a passing cab. Before she can plan her next course, he has bundled himself inside and closed the door after him. Whirling, she finds, like a fairy-tale contrivance, another cab-smaller, seedier-the driver slouched on his box, scoring his cuticle with an apple knife. Reaching into her apron, she draws out three silver coins: the money she has set aside for the wine merchant. "Where do you care to go, Madame?"

Madame. She stares at the wedding ring on her finger. "I was-"

In the end, she can only point at the carriage that is now speeding northward on the Rue Saint-Jacques. The driver requires no further instruction. He cracks his whip three times and sets the horse at a gallop. A block later, he's calling down to her:

"Got 'em! "

He, too, understands the principles of chase. Never let the other fellow know he's being followed. At times, he slows the horse to such a leisurely canter she feels compelled to question him.

"Do you see it? Is it still there?"

And he calls down, easy as water:

"Still there, Madame."

She is glad, after all, that she doesn't have to look at him. If she puts her mind to it, she might imagine herself on a simple excursion, with no destination and no end, except the pleasure of being driven. The vehicle crosses the Pont Notre-Dame, turns right on the Rue SaintAntoine, and she tries to crowd her mind with the prospect of shops and cafes-all those foresworn pleasures.

Five minutes later, without warning, the carriage jolts to a standstill.

"What's wrong?" she calls up.

"They've stopped, Madame."

At first, she sees only a massive stone wall, through whose gate her husband is even now being ushered. The gate closes after him, and her eyes, rising, take in the spectacle of that ugly black square tower, erected all those centuries ago by the Knights Templar . . . the crosses resting atop the turrets like ships' masts . . . an ambience of ancient quarrel.

The Temple.

The implications of her act suddenly radiate outward. She has been spying on her husband, who is, by all appearances, an agent of the Directory. Which makes her guilty of treason. For which, in these otherwise confused times, there is but one punishment.

"I'm sorry," she tells the driver. "I made a mistake. It must have been another carriage."

She asks him to take her back. At once. Not to her house, no, to the corner where she engaged him. Once there, she hands over all her coins and hurries home-harassed the whole way by the memory of the fortress. How, she wonders, can anyone enter such a place and come out alive?

But he does. Strides through the front door at his usual time, a half hour before noon, looking the same as when he left. She can scarcely trust her senses.

"Oh, you're trembling," he says, taking her hand in that efficient grip of his. "Have you caught cold?"

The tremor passes after a few minutes . . . only to overtake her again four years later, when her young son, on a late-summer whim, veers down the Boulevard du Temple. Chasing after him, she finds herself stopped once more by the sight of that charred tower. Feels once more the chill, climbing rib by rib.

"Come, Hector."

She drags him down the street and around the corner, refusing to look back.

Tr ave l fo rwa rd anothe r eighteen years. The boy is grown, the mother has reached a certain age, and the shudder is still there, guttering the tallow candle that stands between them on this Friday evening, agitating the moth inside the ivory lampshade.

"But you only saw him go inside," I say. "How did you know what he was doing there?"

"It couldn't be anything else. Everyone knew the dauphin lived there. Everyone knew how sick he was. Someone had to look after him. Who better than your father?"

"And you never told him."