Gideon could only hear snatches of what was going on in the house, but he gleaned that the woman who lived there was a Secret Service agent working the State of the Union detail, and her family was being held as some kind of leverage. But he still didn’t know for what purpose.

Could it be something as simple as calling the agent up and saying: Kill the president or we kill your family? He didn’t think so. Even if they could count on forcing a Secret Service agent to turn her gun on the president, the event would be over in seconds. Mixon had been very specific: This wasn’t simply an assassination attempt but a “high-value, mass casualty” terrorist attack. And the State of the Union address was definitely the perfect setting for it. But without knowing the agent’s role and assignment, without any word from Nancy, Gideon didn’t think he had enough to take it to Dahlgren. Not if he wanted to convince the man and avoid being arrested.

Much as it pained him, he was going to have to sit tight and wait.

42

WASHINGTON, DC

Wilmot waited as the tank hissed, literally holding his breath.

A pink stream shot out of the tank, vaporizing immediately in the air. Collier turned the tank back off again, leaned down, and breathed in the air near the tank. Wilmot expected him to claw at his throat and fall over, foaming at the mouth and screaming.

But he didn’t.

Instead, Collier straightened and said, “See? Harmless.” He grinned. “Doesn’t smell so great . . . but totally harmless unless you suck in huge quantities of it.”

Wilmot’s pulse slowed. He tried not to look astonished. What the hell had just happened?

The tactical guy closest to Collier nodded to Special Agent Klotz. “Yeah, that’s refrigerant. I can smell it. My brother-in-law tried to fix our heating until last year, busted the line, the stuff leaked into the basement.” He wrinkled his nose. “I had to smell that crap every time me and my buddies played cards down there for two months.”

Special Agent Klotz said, “Okay, gentlemen, I guess we’re good. Let’s go.”

Wilmot followed Collier, Klotz a couple of strides beck d‡hind him, her hand on her gun. Wilmot couldn’t help being impressed. These Secret Service people didn’t mess around.

The long concrete hallway led to the small subway station. A car stood motionless, doors open. Collier started pushing the cart toward the car. Two men immediately barred his way.

“We’re going on foot,” Agent Klotz said. “The subway was rebuilt in the 1960s on a bigger track. The old tunnel is over here. It’s used as a service entrance for the Capitol building now.”

Collier went through the entrance into the second tunnel, the front wheel on the cart wobbling and squeaking loudly. Wilmot followed.

The walk to the Capitol seemed endless. Along the way, Wilmot wondered why the gas had not killed Collier and deduced that Collier had consciously left out some critical details. Was there only gas in one of the tanks? Had Collier just held his breath and relied on the fact that cyanide gas was slightly heavier than air? If it was the latter, eventually the gas would disperse, and the people in the room would start to smell it and probably start keeling over. In which case he and Collier needed to move very fast. But Collier seemed unhurried.

Finally they reached the end of the tunnel, ending up in a small tiled room flanked by an elevator and a set of old iron stairs.

Everything was as he expected it, as laid out on the updated schematics they had reviewed when National Heat & Air got the HVAC contract for the building.

The Secret Service agent said, “Just keep moving, if you don’t mind, gentlemen. We’ll take the elevator.” She spoke softly into her sleeve. “Send the South Capitol elevator to Location L.”

Collier swallowed and started pushing the cart toward the elevator.

A few moments later, the doors opened with an ear-piercing squeak.

43

WASHINGTON, DC

Wilmot and Collier spent all morning in the HVAC Control Room, messing with the controls for the heating system. As planned, it had failed repeatedly. By noon, Wilmot told Shanelle Klotz, “Look, if you want this thing working during the State of the Union, you need us to stay here and babysit.”

“You’re not cleared to stay here.”

“Up to you. Ten to one it breaks down again before evening.”

Several phone calls later, Agent Klotz said, “Okay. You’ll stay here. The door will be guarded. You do not open the door. Knock and the guard will enter. If you need to move to another location, I will have to personally authorize it and accompany you. Clear?”

“Not a problem,” Wilmot said. He sat down and waited until the door closed. They were in a small dark closet of a room. The room had no direct access to the heating unit itself, only to the controller which ran it. There was nothing they could do from this location.

But for the first time, they were alone.

“Okay, t bbbbbbbb t‡so what the hell happened back there?” Wilmot said. “How come we didn’t all die of cyanide poisoning?”

Collier gave Wilmot one of his sour, superior little smiles. “I suspected somebody might need to bleed a tank, so I built them both with double walls. In effect, each one is two entirely separate tanks. The outer chamber contains refrigerant. Turn the cock, you get R410A.” He pointed at the tank. “See this little set screw? I tighten it three full turns and it breaks a seal between the inner and outer chambers. Then when you twist the petcock, instead of getting refrigerant . . .”

“. . . you get cyanide.”

“Exactly.”

“Might have been nice to know that ahead of time,” Wilmot said.

Collier stared at him intently. “I just want you to understand that you still need me. Right up to the end, you’ll need me.”

Wilmot put his hand on the boy’s shoulder. “I’ve never had the slightest doubt about that, son,” he said. “Not for one moment.”

Collier’s face glowed.

Wilmot sat back and put his feet up on the cart. “So you think the system’s going to make it all day without breaking down again?”

Collier smiled broadly. “I strongly suspect it will not.”

44

I-66, OUTSIDE WASHINGTON, DC

Kate Murphy finished putting on her makeup in the car, wishing she could talk to Gideon as the limo crawled through the DC traffic. In just a few hours she would be at the State of the Union address, yet all she really wanted to do was hear his voice.

She had been visited earlier in the day by a particularly unpleasant man—Ray Dahlgren, the FBI’s deputy director—who claimed to want to know Gideon’s whereabouts so he could “help” him. But Kate was no fool; she could spot a phony a mile away, and Dahlgren was as fake as a deposed Nigerian dictator with a bundle of cash. He soon dropped the pretense, and they had a nasty conversation where Dahlgren threw around words like “conspirator” and “obstruction of justice.” Kate laughed off his bullying; but she was worried about Gideon. His voice mail said he was okay, but his investigation had clearly agitated Dahlgren. Now she feared his investigation pitted him against the deputy director and placed him in more danger.

She noted the increased security presence around the Capitol, which seemed intense even by DC standards. She knew the Secret Service left nothing to chance, but she wondered if they had really planned for everything. Threats came from everywhere, at any time, and even the most vigilant security officials could not be omniscient. Now, as the limo idled at a red light, she felt a flicker of concern over whether the State of the Union address could be a target, and whether she would be safe inside.

But she told herself she couldn’t obsess about it. In the post 9/11 world, no one was entirely safe and no place entirely secure. That uncertainty was the new normal. She had to trust Gideon, aned one wd trust that if an attack were planned, he’d find a way of stopping it. The best thing for her to do was to focus on what was right in front of her.