“What’s with the knife?” Vail asked.

“If nothing else, it’s a backup weapon. The letter said no guns. We thought we’d include one with the saw blade because who knows what you’re going to run into. It was developed for clandestine military units.”

Vail snapped the flashlight on and off and opened both knife blades. He took his own lock-back knife out of his pocket and handed it to Kate. Opening the mason’s knife and seeing its honed sharpness, she said, “I’m surprised you thought you needed a gun.”

Vail was reading the demand note and didn’t appear to hear her. “Is that ‘sub’ as in submarine?” he asked.

Tom Demick pulled out a map and laid it on a desk as everyone gathered around. “We’ve reconned the area only by satellite and map. Didn’t want to go stumbling around there with GPSs. It’s in West Hollywood. As close as we can figure, it’s this clear area right here between Lucas Avenue, South Toluca Street, and Beverly Boulevard. There’s no water or submarines around there, but I’ll keeping working on it.”

Kate said, “Seven seventeen is the exact minute of sunset, so you will be working in the dark.”

“I’ll hope that’s not a metaphor.”

“This is the FBI—everything’s a metaphor.”

VAIL LAY HIDDEN in the tall grass between two overgrown shrubs that were against a ten-foot-high chain-link fence. It surrounded a huge vacant lot. According to his wallet GPS, he was still about a hundred yards short of the exact West Hollywood coordinates given in the demand note. He had crawled as far forward as he could. Using the low-light monocular, he searched the area in front of him. When he radioed the information to the major-case room and the covering surveillance cars, he heard Kaulcrick’s voice. “What’s inside the fence?”

“Nothing I can see worth protecting. It looks like a giant vacant lot, maybe the size of one and a half football fields but shaped like a triangle.”

“Do you see anything inside?”

“Nothing.”

“Can you get in?”

“There’s barbed wire coiled all along the top as far as I can see. But the ground inside is not overgrown, so the kids around here probably have a way in and use it to play ball. I guess it’s time to let whoever’s waiting see me.” Vail tucked the monocular into the moneybag, which he hoisted onto his shoulder once he stood up. He started skirting the fence. About sixty yards from where he had parked the car, next to a small footpath that had been worn through the underbrush, he found a hole in the chain link that had been snipped away from the post. He reported what he had found on the radio. “Hold on, Vail, we’re trying to get a satellite picture of the area,” Demick said.

Technology, while providing remarkable advantages to law enforcement, had a crippling side. It could make investigators lazy, keeping them from remaining flexible. Vail was worried that the agents surveilling him were finding it much easier to track him through the GPS monitors in the major-case room than trying to follow him through the dark, irregular terrain. And those were the kinds of vulnerabilities that the Pentad somehow understood and exploited. He pulled back the corner of the fence, pushed the bag in ahead, and squeezed through.

He took out the wallet GPS again to check his position. The destination coordinates had been locked in and an arrow on the screen pointed toward a thirty-foot rise in the ground still almost a hundred yards ahead. He picked up the bag and started toward it. The radio’s earpiece crackled with Tom Demick’s voice. “I think I’ve figured out where you’re going. I should have thought of it before when I heard Toluca Street. It’s the Toluca portal to the old Pacific Electric Railway. I pulled it up on the Internet. It stopped running in the fifties. It used trolley cars. The kind that had the poles that reached up to the overhead electric lines. You’re at the beginning of a mile-long tunnel that was built to circumvent traffic back then, but both ends were sealed off years ago. Located at your end is Substation 51. That’s got to be the ‘sub’ in the note.”

“Very nice, Tom. I’m on my way.”

One of the surveillance teams came up on the radio. “Command, this is One-three, we’re at the fence, and it doesn’t look like we can follow the package without being made. The terrain is too open.”

Vail answered, “I’m good here. The last thing we want is to get burned. I’ll let you know if I need anything.”

“Copy,” One-three answered.

In the major-case room, Kate looked at Kaulcrick. “I don’t like this.”

“Uncertainty is exactly what Bertok wants. Quit worrying. Vail wanted to do this. We’ve got him surrounded. It has to be far enough away that we won’t be made. We’re in far better shape than that debacle in New Hampshire. And we’ve got three monitors up here, each one tracking the different GPSs. Nothing can go wrong.”

Vail’s voice interrupted. “I’m at the substation. It’s a small square building, every inch covered with graffiti.” Involuntarily, his hand went to where his gun should have been, but then he remembered he wasn’t armed. “Let’s go to radio silence until I see what’s inside.” He carefully stepped up onto the landing in front of the door and then moved against a wall as he listened. He couldn’t hear anything. He peeked inside.

Three glowsticks formed an arrow like he had read about in the naval-prison report. Next to it were two others holding down a sheet of paper. The room was otherwise empty. He went in and picked up the note. Underneath it was a walkie-talkie with the transmission key soldered into a permanent transmission position. The extortionists were now listening to him. He read the note:

Do not transmit one more word on your radio.Take this radio, clip it to your belt, and leave yours here. Follow the arrow.

After carefully folding the note and putting it in his pocket, Vail opened his shirt and peeled the microphone from his chest, pulling the Bureau radio from his waistband. He dropped it loudly on the floor so the extortionist’s radio could hear it being discarded and then attached their radio to his belt. That answered the question why they didn’t want him to bring a cell phone—it could be used for silent text-messaging.

The arrow was glued to a couple of rocks. It pointed toward the sealed entrance of the railroad tunnel. But the rocks used seemed to have a secondary direction. Their difference in height also made the arrow rise, almost as if it was pointing to the top of the tunnel. Vail stepped out of the building and stood still for a moment, making sure the satellites could once again lock onto the two remaining GPSs. He starting walking slowly toward the entrance to the tunnel.

“Steve, what’s happening?” Kate said into the mike. “Steve?”

“Something must have happened to his radio,” said the agent watching the monitor for the GPS on his body transmitter. “Even though he’s moving away from the substation, the monitor shows the radio’s still in the building.”

The headquarters tech agent had been hovering between all three monitors and said, “They must have had him take it off and leave it there. It’s okay. That’s why we gave him two backups. They’re still working fine.”

“But we can’t communicate with him,” Kate said.

Kaulcrick spoke into the radio mike. “One-one, do your people have the area surrounded?”

“As best we can without getting too close.”

“Just make sure if he leaves that fenced-off area, he can’t get by you.”

“I don’t like this,” Kate said again. “At each turn, we’re losing more control.”

Vail had reached the mouth of the tunnel. The arched entrance was an almost perfect half circle about twenty feet high. It had been sealed up with cinder block and coated with a concrete plaster. Like the substation, it shimmered electrically with graffiti of all colors in the low light.