“The first clue was the gunpowder in the lights. Since he’s an engineer, Calculus would have known that as an antipersonnel mine it would inflict just minor wounds, because the only projectiles would have been the bulb’s glass, which would have broken into very small fragments.”

“Then why would he rig them?”

“Besides the explosion and the flying glass, what else happened?”

“The fireball from the explosion, which would probably have caught some things on fire if it hadn’t been for the sprinklers.”

“Exactly, the sprinklers. That was his purpose. When I saw the bowl directly under the heads in that hidden room, it didn’t seem right. The ink on the outside of the packet had caused the paper to deteriorate slightly. I think it’s made of water-soluble paper, so when it got wet, it would expose whatever powder is inside to more water. I think his intention was for us to destroy the disc.”

“Why would he direct us to the disc and then want to destroy it?”

“If he was still here to work with us on the list, he would have told us about the booby-trapped lights and the powder. But he put them in place so if the Russians somehow got onto him, we would hopefully beat them to the disc and unwittingly destroy it so they would have no proof against him. And if the Russians got there first, and he didn’t tell them about the lights, they would destroy it.”

“How’s a plastic disc going to be destroyed by water?”

“There’s also the powder. Did you have high-school chemistry?”

“No.”

“I think it’s potassium, which when exposed to water has a violent chemical reaction. It would have turned the disc into liquid plastic. That was the bad news, but since we got it without any damage, that leaves the good news.”

“Which is?” she asked.

“That he wrote the name ‘Ariadne’ on it.”

“Who’s that?”

“It’s from Greek mythology. She was the lover of Theseus, who volunteered to kill the Minotaur, a creature that was part man and part bull. It was kept in this complex maze from which it would have been impossible for Theseus to escape after killing it. So Ariadne gave him a golden cord to find his way out. In Logic, there’s a process referred to as Ariadne’s thread. It’s used to describe the solving of a problem that has a number of ways to proceed.”

“So that means what?”

“I’m hoping Calculus’s choice of ‘Ariadne’ means there’s a subtle set of clues for us to follow from mole to mole.”

“But he wanted to sell each name to us, one at a time. Why would he link them all together with the possibility of our being able to find them on our own?”

“Let’s not forget he tried to get us to destroy the first clue and any others that might have evolved from it so the Russians couldn’t retrieve them to use against him. We weren’t supposed to come out of that house with the disc unless he was controlling the situation. Again, it’s like the maze: Even if you killed the Minotaur, your punishment was that you’d never be able to find your way out. And as far as why he would provide a link from one to the others, he’s a smart guy, probably smarter than his pay grade.

“Most spies have one thing in common,” he continued. “They believe they’re underpromoted and underappreciated. They have contempt for everyone around them. Maybe he put the link in there to prove how much smarter he is than everyone else—the Russians because he’s selling their secrets under their noses and the FBI because we had the answer and didn’t realize it. Probably after he’d led us to the moles one by one, he would have exposed how they were all linked together, thereby proving how inept we are. It’s like some serial killers. They’re compelled to send solid but subtle clues to the newspaper and the authorities as to their real identity. And when they’re caught by some other means, the media will look at the clues and say, ‘How could the police not have figured it out?’ Then, even after they’re caught, they have eternal revenge against the legal system by letting everyone second-guess the cops’ inability to decode the ‘obvious.’ It’s all about control and ego.”

“Maybe he was hoping that if something went wrong and we were able to follow the string on our own, we’d do the honorable thing and send the money off to Chicago?” Kate said.

“Actually, that’s a more pragmatic analysis than mine. This is America—maybe he thought we would do the right thing.”

“So if there is a cord, not only will we have evidence on that disc of Pollock’s spying, there’ll also be a lead to the next mole.”

“Unless I’m wrong.”

She adjusted the heat vent so the air blew directly on her soaking hair and started running her fingers through it, trying to dry it. “Don’t be absurd. You, wrong? That hasn’t happened, for . . . what? Almost fifteen minutes?”

6

It was almost 11 P.M. by the time Vail changed clothes, and he and Kate drove back to FBI headquarters. At the lab Nate Wilhelm introduced himself as being from the Chemical Unit. Vail took out the plastic-bag-wrapped packet and handed it to him. “We think there’s a disc inside the envelope and that it’s covered with some water-catalyst powder, possibly potassium, meant to destroy it,” Kate said. “The envelope appears to be water-soluble, too.”

Wilhelm pulled on a pair of thick latex gloves. “Do you need to preserve the package for prints or handwriting?”

Vail looked at Kate. She said, “Just to be on the safe side, you’d better try.”

The examiner put on a pair of safety glasses and a dust mask. Then, with an X-Acto knife, he slit open the end of the envelope. Careful not to drag out any more powder than necessary, he used a pair of padded forceps to remove the disc from the paper container. He took the packet to another workstation and shook out all the powder he could. Then he put a small amount of it into a test tube. Using a pipette, he dripped a couple ounces of water into the tube. The powder bubbled furiously. “It looks like potassium, and it reacts to water like potassium.”

He pulled off the gloves and put on a fresh pair, going back to the disc. He dusted it off with a large fingerprint brush, then held it up to the light. “No latents.” Out of a box that dispensed them, he took a sterile cloth and wiped the disc off on both sides. He did it twice more with fresh cloths and then took off his mask, glasses, and gloves. “That should do it.”

Vail took it by the edges and touched his fingertip to the non-play side of the disc, testing it for any reaction to the moisture from his hand. There was none. He asked Wilhelm for a plastic protective sleeve and dropped it into his side jacket pocket.

Kate said, “Nate, we don’t want this to show up on any paperwork. Will that cause you any problems?”

“Less paperwork is never a problem, Kate.”

“Thanks.”

As Kate and Vail started toward the elevator, he said, “Should we wait until tomorrow to see what’s on this?”

“Like you could wait.”

He laughed. “I was just trying to see how tired you were.”

When the elevator door opened, the only passenger, a black man, said, “Steve Vail?”

It was Luke Bursaw, an agent Vail had worked with in Detroit more than five years earlier. “Luke,” Vail said, shaking hands with him. “What are you doing here?”

“I finally got my ‘office of preference’ transfer. I’m at the Washington Field Office now, working general criminal. Are you back with the Bureau?”

Vail looked at Kate. “I’m sorry. This is Kate Bannon. She’s—”

“Sure, I remember Kate from Detroit. And now she’s a deputy assistant director. We get most of the memos over at WFO. How are you, Kate?” He extended his hand.

Kate took it. She remembered him because he was the only agent Vail had worked with in Detroit, usually when a difficult arrest needed to be made. The most memorable one was where Vail and Bursaw came barging into the office with four bank robbers handcuffed together early one morning. One of them, also wanted for murder, had been on Michigan’s ten-most-wanted list. It happened shortly after she’d arrived in Detroit, and the thing that had always stuck with her was that no one seemed to think it was out of the ordinary, at least not for Vail.