Robert Halton smiled and stroked his daughter’s cheek. The two had been nearly inseparable since the death of Halton’s wife five years earlier in a private-plane crash in northern Alaska—so inseparable, in fact, that Halton had refused to accept the president’s offer to become his envoy to London until first making certain Elizabeth would accompany him. While most young women would have leaped at the chance to live in London as the daughter of the American ambassador, Elizabeth had been reluctant to leave Colorado. She was one of the most highly regarded emergency-room surgeons in Denver and was discussing marriage with a successful real estate developer. She had wavered for several weeks, until one evening, while on duty at Denver’s Rose Medical Center, she had received a call from the White House on her mobile phone. “I need your father in London,” the president had said. “What do I have to say to you to make that happen?”

Few people were better positioned to turn down a request from the commander in chief than Elizabeth Halton. She had known the president her entire life. She had skied with him in Aspen and hunted deer with him in Montana. She had been toasted by him on the day she graduated from medical school and comforted by him on the day her mother was buried. But she had not turned him down, of course, and upon her arrival in London had thrown herself into the assignment with the same determination and skill with which she approached every other challenge in life. She ruled Winfield House with an iron hand and was nearly always on her father’s arm at official events and important social affairs. She did volunteer work in London hospitals—especially those that served the poor immigrant communities—and was a skillful public advocate for American policy in Iraq and the broader war on terror. She was as popular with the London press as her father was loathed, despite the fact that the Guardian had published a little-known fact that Elizabeth, for reasons of security, had tried to keep secret. The president of the United States was her godfather.

“Why don’t you skip the newspapers this morning and come out for a run with us?” She patted his midsection. “You’re starting to put on weight again.”

“I’m having coffee with the foreign secretary at nine. And don’t forget we’re having drinks at Downing Street tonight.”

“I won’t forget.”

Robert Halton folded his newspaper and looked at his daughter seriously.

“I want you and your friends to be careful out there. NCTC raised the threat level in Europe yesterday.”

NCTC was the National Counterterrorism Center.

“Anything specific?”

“It was vague. Heightened activity among known al-Qaeda cells. The usual crap. But that doesn’t mean we should ignore it. Take a couple Marines with you for good measure.”