“Get on to Diplomatic Security,” Graves continued. “See if any foreign dignitaries are slated to visit any of the agencies on the list. Then contact BERR’s chief of security. Tell him to lock down the place until we arrive. We’ll be over in ten minutes.”

“What about traffic?” asked Kate. “Shouldn’t we block off all roads leading to the building?”

“If we locked down traffic every time we had a threat, London would go out of business in a fortnight.” Graves looked at his assistant. “Get the demo boys over there. Can’t hurt.” He stood and faced Kate. “I take it you’re joining me.”

Kate, Graves, and Cleak took the elevator to the ground floor, where Graves ’s Rover had been brought round and stood waiting, engine idling, doors open. Kate climbed into the front seat next to Graves, while Cleak slid into the back. The blast barrier was lowered and Graves accelerated onto Horseferry Road, where he quickly became enmeshed in traffic. The Rover advanced slowly, making it through one signal, then another. Kate glanced at the clock: 11:03.

“Got a flasher?” she asked, referring to a portable siren.

“Afraid not. We’re more in the preemptive line of things.”

The traffic light changed and Graves pulled across the intersection. After traveling 50 meters, he came to another halt. Victoria Street was less than two kilometers away. In reasonable conditions, the drive would take three minutes. As it was, they were looking at upwards of twenty.

Graves was on the phone with his assistant. “No foreign parties visiting BERR today,” he said to Kate, relaying the news as he received it. “The minister is in Leeds. Everything’s business as usual.”

The car inched forward.

Kate noted that Graves ’s cheeks were flushed and that he was batting his hand against the steering wheel. “Maybe we should walk,” she suggested.

“Forget it.” Graves studied the road in front of him, his blue eyes no longer so divinely certain. Suddenly he swung the car into the oncoming lane of traffic. The road was clear for 30 meters. He floored the Rover, keeping his palm on the horn, until a lorry forced him back into his own lane.

Again they came to a dead halt.

The clock read 11:06.

Five minutes later they reached the intersection of Victoria Street. Graves turned right and sighed with relief when he observed that traffic was flowing nicely. He accelerated to 80 kilometers an hour, rocking in his seat, mumbling, “Come on.” The light turned red and he braked hard.

“There it is,” said Kate, pointing to a modern office building 300 meters along the road.

“Thank God,” registered Cleak from his post in the rear seat.

The light turned green, but the traffic didn’t move. The driver of the vehicle in front of them opened the door and put a foot on the pavement. Kate got out of the car. “They’re running a temporary road block,” she said, sticking her head into the cabin. “Someone’s coming through. Raja from Whitehall or a visiting dignitary. I thought you said there was nothing scheduled for the area.”

“I said nothing was scheduled inside the building.” Graves threw open the door and climbed out. He had his cell phone to his ear, but Kate couldn’t make out to whom he was talking.

Just then she caught sight of the first car in the motorcade barreling out of Storey’s Gate and turning in front of them onto Victoria Street. It was a black Suburban, windows tinted, riding low to the ground. An armored vehicle moving at speed.

“Who’s in town?” she asked Graves. “Looks like the bloody president of the United States.”

Graves was shaking his head. “I’ve got nothing on this,” he said, his calm suddenly in short supply.

Somewhere in the distance Kate caught the sound of a man shouting. Over the roar of the passing motorcade she couldn’t make out what he was saying. It sounded like he was calling someone’s name. One thing was for sure: he was worked up.

“Do you hear that? Something’s wrong.”

“Where?” asked Graves, only half listening. He was conducting a running skirmish with the office, demanding to know what foreign dignitary was in the city and why he hadn’t been informed about it.

Kate stood on her tiptoes, craning her neck in an effort to locate the source of the shouting. About 300 meters up the sidewalk, she caught sight of a dark head running toward them. The head bobbed up and down. Visible one instant, gone the next. It belonged to a white male. Graying hair. Blue jacket. More than that she couldn’t tell.

A second Suburban shot into the intersection, followed by a trio of Mercedes sedans, all black, all with windows similarly tinted to prevent unfriendly parties from identifying their occupants. A miniature flag flew from the antenna of the lead Mercedes. She recognized the blue, white, and red tricolor of Russia.

She checked her watch. It was 11:15.

Mischa, she thought.

Seated in the rear of the cab, Jonathan watched Emma climb from the BMW and walk away from the car. He had his money ready and as soon as Emma had gone ten steps, he passed the cabbie two fifty-pound notes. He waited another moment, his eyes fixed on his wife as if there were a cable connecting them, then opened his door and set off down the sidewalk. He kept close to the buildings, slowing now and again to keep some pedestrians between him and his wife. “Natural cover,” she’d called it, explaining her work to him.

Emma continued down Storey’s Gate for exactly one block before stopping at the intersection of Victoria Street. The light changed. Pedestrians on either side of her crossed the street, but Emma remained where she was.

Jonathan hung back, watching. Any second now, a car was going to pull up, Emma was going to climb in, and that would be that. He would never see his wife again. He turned, looking for a cab, but for once there were none to be seen. He balled his fist and pounded his thigh. He should never have abandoned the taxi.

It was almost 11:15. Dr. Blackburn would be frantically searching for him at the hotel, wondering where his keynote speaker had disappeared to. He imagined Jamie Meadows pounding on the door of his hotel room, asking if everything was all right. Jonathan put them out of his mind. He could give his talk tomorrow.

It was then that he saw a motorcycle policeman zip past him, and all thoughts about the conference vanished. The policeman continued to the intersection of Storey’s Gate and Victoria Street, where he stopped his bike, dismounted, and blocked off all eastbound traffic. Quickly the road emptied of vehicles and grew curiously calm. Jonathan was put in mind of the eerie silence that precedes an avalanche.

By now a group of pedestrians had surrounded Emma. Even so, he could see her clearly standing with a cell phone to her ear, gazing intently in front of her.

Behind him, he heard the hum of a powerful engine. He turned in time to see a flash of black, and a Chevrolet Suburban zipped past him, then another identical to it, close behind. Both were followed by a fleet of jet-black Mercedeses. Three in all. He saw a flag fluttering from one of the cars. The red, white, and blue of the tricolor shimmered in the bright sunshine. It took him a few seconds to guess the country. Not France, not Holland … Russia .

It hit him then. He knew why Emma was waiting at the corner.

Lebanon. Kosovo. Iraq . She had told him about her work in those places. Invariably it involved the kidnapping or assassination of a high-ranking figure deemed unfriendly to the cause-the cause being the security and well-being of the United States of America. It was no coincidence that she was standing on this particular street corner at the precise moment that a motorcade ferrying Russian officials across London was passing.