“Nothing with brass buttons,” she said. “You should wear a suit, anyway; the Waterside Inn is quite elegant.”

Stone went away and came back with a suit jacket. She examined the buttons and nodded, then opened her briefcase. She removed a small leather case, which held a selection of buttons. “Oh, good,” she said; “an excellent match.” She took some scissors and snipped off one of the four small buttons on Stone’s left sleeve, then deftly sewed on one of her buttons. “There,” she said. “Good match?”

“Excellent. Do you mean that tiny button is a bug?”

“In conjunction with this,” she said, holding up a fat Mont Blanc pen, made of sterling silver. She clipped it into Stone’s inside left-hand pocket. “The button transmits to the pen, and the pen transmits up to three miles, but we’ll keep the van within two, just to be sure. They pick up the transmission and record it.” She took out the pen and unscrewed the cap. “It’s a working pen, too.”

Stone examined the pen and tried to unscrew the other end.

“You can’t do that without a special tool; don’t worry, it has a fresh rollerball refill inside; you won’t run out of ink.”

“Good,” Stone said, replacing the pen in the jacket pocket.

“The only limitation is that the button has to be within six feet of whoever you’re talking to. I used a sleeve button because you can put your hands on the table and get it closer to Cabot. Don’t have any conversations with him from across the room.”

“I’ll remember that,” he said. “Tell me, how did a nice girl like you get into this business?”

“Isn’t that what you’re supposed to ask a whore?” she asked wryly.

“Spies, too.”

“I’m not a spy; I catch spies.”

“Come on, how?”

“I was recruited my last year at Oxford; my father had worked for the same firm, but he was killed in the line of duty when I was sixteen. I suppose I wanted to finish his job. How did you get from being a cop to being a lawyer?”

“I was recruited for the police department my last year in law school,” Stone said. “Fourteen years later, I was retired for medical reasons. I took the bar exam, and a friend found a place for me with his law firm.”

“You look pretty healthy to me,” she said, looking him up and down.

“It was a bullet in the knee. I got over it, except in cold weather.”

“Oh,” she said, retrieving a map from her briefcase. “Sit down, and I’ll show you how to get to the Waterside Inn.”

Stone sat on the arm of her chair and caught a faint whiff of perfume. He wondered if intelligence agents often wore perfume to work.