“Anything to get you out of my bloody hair.” Lloyd-Philips tapped the tech on the shoulder, the tech asked for the number of Marks’s cell, then pressed a button; a moment later a digital still from the security tape of the two men side by side appeared on Marks’s phone.

“All right, then.” The chief inspector turned to Marks. “Don’t make me regret what I’ve done. Stay well away from me and my case and you’ll get on well.”

Back out on the street, the sun was struggling to be seen through masses of streaming cloud. The city roared all around Marks. He checked the photo on his PDA. Then he punched in Willard’s private line and got right to his voice mail. Willard’s phone was off, which, calculating the hour back in Washington, Marks thought odd. He left a detailed message, asking Willard to run the photo of the man who had knifed Diego Hererra through the Treadstone data banks, which had been amassed from those of the usual alphabet soup of CI, NSA, FBI, DoD, plus some others to which Willard had gained access.

From a detective-inspector outside the club to whom he showed his ID, Marks obtained Diego Hererra’s home address. Forty minutes later he arrived just as a silver Bentley limousine turned the corner and pulled up outside Hererra’s house. The liveried driver emerged, walked smartly around the gleaming grille to open the rear door. A tall, distinguished man who looked like an older version of Diego emerged. With a somber expression and a heavy tread the man climbed the steps to Diego’s front door and inserted a key in the door.

Before he could disappear inside, Marks strode up and said, “Mr. Hererra, I’m Peter Marks.” When the older man turned around to peer at him, Marks added, “I’m terribly sorry for your loss.”

The elder Hererra paused for a moment. He was a handsome man, with a leonine shock of white hair, worn long over his collar in the current Catalan style, but he appeared ashen beneath his deep outdoorsman’s tan. “Did you know my son, Señor Marks?”

“I’m afraid I didn’t have that pleasure, sir.”

Hererra nodded somewhat absently. “It seemed Diego had very few male friends.” His mouth twitched in a parody of a smile. “His preference was for women.”

Marks took a step forward and held his creds up for the other to see. “Sir, I know this is a difficult time, and I apologize in advance if I’m intruding, but I need to talk to you.”

Hererra continued to look through Marks as if he hadn’t heard a word he’d said. Then he seemed to focus. “Do you know something about his death?”

“This isn’t a conversation for the street, is it, Señor Hererra.”

“No, of course not.” Hererra’s head twitched. “Please forgive my lack of manners, Señor Marks.” Then he gestured. He had very large, square hands, the capable hands of a skilled laborer. “Come inside and we’ll talk.”

Marks went up the steps, across the threshold, and into the late Diego Hererra’s house. He heard the older man coming in after him, the door close behind him, and then there was a knife blade across his throat, and Diego Hererra’s father was close behind him, holding him in an astonishingly powerful grip.

“Now, you sonovabitch,” Hererra said, “you’ll tell me everything you know about my son’s murder, or by Christ’s tears I’ll slit your throat from ear to ear.”

17

BUD HALLIDAY SAT in a semicircular banquette at the White Knights Lounge, a bar in an out-of-the-way area of suburban Maryland where he often came to unwind. He nursed a bourbon-and-water while he tried to clear his mind of the clutter that had built up over the long day.

His parents were Mainline Philadelphians who could trace their respective families back to Alexander Hamilton and John Adams, respectively. They had been childhood sweethearts who, with the predictability of their ilk, were divorced. His mother, a society doyenne, now lived in Newport, Rhode Island. His father, plagued with emphysema from years of inveterate smoking, rattled around the family mansion, trailed by oxygen tanks and a pair of full-time Haitian nurses. Halliday saw neither of them. He’d turned his back on the hermetically sealed golden glow of their society world when, to their horror and mortification, he had gleefully enlisted in the marines at the age of eighteen. While at boot camp he had imagined his mother fainting at the news, which gave him a great measure of satisfaction. As for his father, he’d probably chewed off the end of his cigar, blamed his wife for his disappointment, and gone off to the insurance company he owned, and which he ran with ruthless and appalling success.

Finding that he’d finished his bourbon, Halliday flagged down the waiter and ordered another.

The twins arrived at the same time as his drink, and he ordered them chocolate martinis. They sat down on either side of him. One was dressed in green, the other in blue. The one in green was a redhead, the other blond. Today, at least. They were like that, Michelle and Mandy. They liked to play off their eerie echoes of each other, but at the same time asserting their differences. They were tall, almost six feet, with figures as lush and luscious as their lips. They could have been models, or possibly even actresses, given the expert way they played roles, but were neither vain nor empty-headed. Michelle was a theoretical mathematician, and Mandy was a microbiologist at the CDC. Michelle, who could have had her pick of chairs at any of the top universities in the country, instead worked for DARPA-the Defense Advanced Research Projects Agency-cooking up new cryptographic algorithms that could foil even the fastest computer, even used in tandem. Her latest used heuristic techniques, meaning it learned from every attempt to break it, as if it were a self-educating entity, changing on the fly. It required a physical key to unlock it.

Never had two more fertile minds been wrapped in such delectable and erotic packages, Halliday thought as the waiter set their chocolate martinis in front of them. They all raised their glasses in a silent toast to another night together. When they were off duty, the girls loved sex, chocolate, and sex, in that order. But they weren’t off duty yet.

“What’s your assessment of the ring?” Halliday asked Michelle.

“It would help,” she said, “if you had given me the real thing instead of a set of photos.”

“Given that I didn’t, what’s your best guess?”

Michelle took a sip of her drink as if needing time to set her thoughts in order or to figure out how to express them to Halliday, a mental midget compared with her and her twin.

“It seems likely to me that the ring is a physical key.”

Halliday got interested in a hurry. He was keeping a sharp lookout. “Meaning?”

“Just what I said. It may be the algorithm I’m working on, but the odd inscription on the inside of the ring appears to me to be like the ridges of a key.” Responding to Halliday’s quizzical look, she changed tack. Taking out a felt-tip pen, she drew on Halliday’s napkin.

“Here we have a common key to a lock. It has ridges cut into it that are unique to it. Most common locks have twelve pins inside the lock cylinder, six upper and six lower. When the key is inserted in the cylinder, the ridges raise the upper pins above the shear line, allowing the shaft inside the cylinder to turn and the lock to open.

“So now consider each ideogram of the engraving inside the ring as a notch. Slip the ring into the right lock and presto, Open Sesame.”

“Is this possible?” he asked.

“Anything’s possible, Bud. You know that.”

Halliday stared at her drawing, suddenly galvanized. Her theory took a big leap of faith to believe, but the woman was a stone-cold genius. He couldn’t afford to dismiss any theory she put forward no matter how loopy it might sound on first blush.

“What’s in store for us tonight?” Mandy asked, clearly bored with this topic.