Alex scrubbed a hand across his face. He was a weird combination of keyed up and exhausted. “Well, thank you very much for coming out in the middle of the night, or, whatever, I guess it's the morning,” he said.

“Not a problem, sir,” Randol said. “We're glad you're okay.”

Alex left every light on after they left. He knew it was ridiculous, but he couldn't help thinking: What if he comes back?

But come on. A burglar coming back to the same house he got surprised at and ran out of earlier the same night? The police might be there, who knows what.

Ridiculous.

The way Randol had opened the front door, though… that was unbelievable. The miracle wasn't that Alex had gotten away tonight; it was that no one had tried to rob him until now.

Not that the guy would come back. But if he did, it wasn't like Alex could stop him. There was effectively no lock on the door, he didn't own a gun.

He remembered the sound the door had made as it slid stealthily open. How terrified and vulnerable he had felt in the bath.

The hell with it. He'd just stay at the Four Seasons in Palo Alto. He did enough business meals in their Quattro restaurant. Might as well sleep there tonight. If he stayed here, he would lie awake the rest of the night, imagining every joint that settled was a footstep, every whoosh of the gas heater the sound of the front door again.

He grabbed a change of clothes and looked through the front window long and hard before venturing out.

Alex slept fitfully for a few hours at the hotel. When he woke up, the brilliant Bay Area sun was shining through the windows onto the white bed linens. He scrubbed his face and thought about the night before. At the time, he'd been panicked and confused. He had thought it was just a burglar. But now, he realized he'd been missing something obvious.

The inventor killed, Alex's contact at the patent office dead, and someone breaking into his house, all in the space of what, thirty-six hours? You didn't have to be a conspiracy theorist to believe coincidences didn't happen like that.

What were those games he had liked to play in Highlights magazine when he was a kid? What do these things have in common?-that was one of them. There would be a bunch of seemingly disparate pictures, but if you looked closely, if you thought about it, you'd realize they all had right angles, or all began with the letter A, or whatever.

What Alex, Hilzoy, and Hank all had in common was Obsidian. Even if it was a coincidence, the overlap was obvious. The question was, why? What was it about Obsidian that led to someone wanting to kill for it?

No, it didn't make sense. Companies that wanted to acquire a promising technology or neutralize a threatening one did it with cash. It was easy, and it was legal. Hell, Hilzoy could have been had for under seven figures. That wasn't even a rounding error for players in the computer security field.

But whoever was behind all this, how did they even know about the technology? The patent application was secret.

Well, something could have leaked. Who knows who Hilzoy might have told? Who knows who saw what in the patent office? And it wasn't as if Obsidian was for Alex's eyes only at Sullivan, Greenwald. There was Osborne, for one, and of course Sarah.

He told himself he was probably being ridiculous, but better safe than sorry. He called Detective Gamez on the mobile number on the man's card. He told him about the break-in. He told him he knew it sounded crazy, but… What if Hank's death hadn't been a heart attack? How sure were they? Because the inventor and the examiner-it just seemed like quite a coincidence, no? To his surprise, Gamez didn't treat him like he was a nut job. He told him he would look into it and call Alex back.

Alex drove to the office. The first thing he did there was call a locksmith. It was going to be hard enough to sleep in the house after what had happened. Turning the place into a fortress would make it a little easier. Then he called a gun shop. Apparently, he could buy a gun but would have to wait ten days to pass a background check before picking it up. Shit, he'd always thought background checks were a good idea. But he needed something right now.

Gamez called him back. He said, “All right, I talked to the Arlington cops. They already autopsied Shiffman. The family wanted it- Shiffman was young and healthy, and the family was concerned there might be some genetic predisposition that could affect other members of the family.”

“Well, what did the autopsy show?”

“Inconclusive. They think it might be something called Brugada syndrome.”

“What's that?”

“Apparently it's a genetic condition that accounts for sudden death in otherwise healthy males, most of them in their thirties, often while they're sleeping. It's not that well understood.”

Alex thought it sounded like something someone made up so doctors wouldn't have to tell the bereaved, Sorry, we don't have a clue.

“Do you know… is it likely they'll have any kind of definitive explanation?”

“They're doing genetic testing and a family history. But you want my opinion? No one's ever really going to know. Sometimes people just keel over and there's no explanation. It happens.”

“So you think this was just… a heart attack?”

“I talked to the homicide lieutenant in Arlington. They examined Shiffman's apartment, routine for a death like this. No sign of forced entry. No evidence of a struggle. And there were no marks of any kind on the body. If that's a murder, I'd like to know how it was done.”

“So you think I'm being paranoid.”

“No, I don't think that. It's a hell of a coincidence, no doubt about it.”

“I don't know what to do.”

“Apart from the break-in, have you noticed anything unusual? Anyone loitering near your car in the office parking lot, anyone following you while you're driving, anyone outside your house when you leave for work?”

“No. Nothing.”

“Well, you've got my number. Be alert, and if anything rubs you the wrong way, call me.”

“Thanks.”

“Not a problem.”

Alex hung up and looked at the phone for a moment. Somehow the fact that Gamez was so sure Hank had just died of a heart attack made him edgy again. Because the truth was, they didn't really know.

What if none of this was a coincidence? If someone was after him, they knew where he lived. They'd known where Hilzoy lived. They'd gotten to Hank. They would know where Alex worked. They'd know what he looked like-hell, his photo and professional bio were right there on Sullivan, Greenwald's Web site, available to anyone anywhere. So what was he supposed to do? Stop living in his house? Stop going to work? He thought he'd felt naked in the bathroom that night, but he felt more exposed now.

A thought was trying to bubble up from somewhere deep inside him. It felt more like an instinct, a reflex, than a thought. A single word, a syllable, and it was-

Ben.

No. Katie, then their father… and he'd visited home, what, twice while their mother was wasting away with cancer? She ‘d been in a coma for three days at the end, and Ben hadn't managed to get back to be with her even then. Too busy playing army to be with his own mother when she died. Didn't they have compassionate leave in the military? Jesus, it was a miracle the bastard had even bothered to show up for the funeral.

He blew out a long breath. His useless brother. Football hero. Wrestling star. G.I. Joe. But when the going really got tough, he was the invisible man. And now Alex was supposed to go crawling to him, begging him for his help?

Anyway, help how? What could Ben do?

He had a lot of training, Alex knew that. He'd been a Ranger in the battle of Mogadishu and had won a bunch of medals. Alex had seen the movie Black Hawk Down and couldn't imagine Ben, tough as he was, doing all that, but apparently Ben had. And after that he'd been a Green Beret or something. So for Christ's sake, if anyone could help…