Kate stepped away from Graves and began heading up Storey’s Gate, past the site of the explosion. Just before the blast she’d heard a man yelling some kind of warning. Strange, but she’d forgotten about it until Graves had mentioned the need to preserve evidence. She recalled seeing a cap of graying hair, a navy jacket.

By now men and women were streaming out of the buildings on both sides of the road. In case of terrorist attack, city law called for the mandatory evacuation of all buildings and residences in the area. Many hurried up the street, anxious to escape. Others lingered, exhibiting a morbid curiosity about the blown-up vehicles and the fate of those inside.

Kate walked against the tide. Victims of the blast lay on the sidewalk. Most seemed to have superficial wounds: bloody noses caused by the concussion of the blast, ruptured eardrums, cuts inflicted by flying glass, shock. She paused to let them know that help was on its way, then continued her search.

Graying hair. Navy jacket. She saw no one who fit the bill.

There was a crater where the bomb had gone off. The car itself sat twisted and in flames 3 meters away. As she passed it, she raised a hand to ward off the ferocious heat. Black smoke rose into the sky, mixing with dust and debris, burning her eyes and making it difficult to see. She held a hankie to her mouth, but even then the air was hot and choked with soot. She began to cough.

Another Mercedes lay burning 10 meters up the street. Suddenly a man fell out of the vehicle and began to crawl away from it. A halo of flames surrounded his head. Clothing hung in tatters from his arms and chest, but his back appeared to be flayed to the bone. She heard a voice yell, “Lie down” and saw another man running to his assistance, throwing a jacket over his head and extinguishing the flames. The Samaritan had graying hair, and the jacket he’d used to put out the flames was a navy blazer.

Kate radioed Graves. “I’m halfway down Storey’s Gate. Get over here. I’ve found the man I was looking for.”

Within seconds Graves was by her side, two policemen in tow. “Where is he?”

“That’s him. Kneeling next to the injured man.”

Graves shouted instructions, and one of the policemen ran forward and threw the man to the ground.

“Don’t touch him!” shouted the Samaritan, his words clear, the American accent pronounced. His face was covered in blood, but he sounded strong and in control of his wits. “He has third-degree burns all over his body. Get a poncho and cover him up. There’s too much debris in the air. You have to protect the burn or he’ll die of infection.”

Kate knelt beside him. “What’s your name?” she asked.

“Ransom. Jonathan Ransom. I’m a doctor.”

“Why did you do this?” she demanded.

“Do what?”

“This. The bomb,” said the woman. “I saw you shouting at someone back there. Who was it?”

“I don’t-” The man bit back his words.

“You don’t what?”

For a long moment, the man didn’t answer. He stared past her, and for a minute she thought he had fallen into a state of shock. Finally he looked at her. “I don’t know,” he said.

Then he laid his head down on the pavement and closed his eyes.

From Division’s office in Lambeth, south of the Thames, Frank Connor heard the blast and immediately turned on the television. A bulletin cut into programming within five minutes. A still photograph of the Department of Business, Enterprise, and Regulatory Reform was displayed as a reporter offered the first sketchy details of a car bombing near Victoria Street, in the heart of London. A rattled eyewitness followed, describing the blast.

Connor watched intently, popping open a can of Coca-Cola and sneaking glances out the window. It wasn’t long before he caught the plume of smoke drifting above the skyline. He knew about explosions, and this one was a monster.

One of the desk girls entered the room. “I’ve tracked down Hubert Lorenz,” she said. “He’s available, but he’s asking for one hundred thousand pounds.”

Lorenz was a German bounty hunter known in the trade for his precision and reliability.

But Connor didn’t answer. If anything, he drew nearer the television, his eyes transfixed by the pictures now being beamed live from the scene. The camera panned over several mangled automobiles and lingered on bloody victims lying on the sidewalks. The reporter announced that seven people were confirmed dead and at least twenty injured. Connor was surprised the numbers weren’t higher.

“I’ve got him on the line,” continued the assistant in her aggravating north-of-England accent. “He’s not someone who likes to be kept waiting.”

“Yeah, yeah, just hold on.” Connor turned up the volume. The reporter announced that the target of the attack was thought to have been Igor Ivanov, the Russian interior minister, and added that Ivanov had been taken to a nearby hospital, where news of his condition was expected at any minute. “And?” Connor whispered to himself, like a bettor with an interest in the game. “Is he dead or alive?”

“Mr. Connor, what do I do about Mr. Lorenz?”

Connor spun in his chair. “Tell him to fuck off! Can’t you see I’m busy?”

“Excuse me?”

“You heard me. Get out. I’m fuckin’ occupied!”

The assistant beat a quick retreat.

Connor rose and opened the window. By now the smoke had spread into an ominous black pall that enveloped Big Ben and covered a good portion of the sky. Helicopters flitted low over the skyline. The wail of sirens sounded from every direction. Once again London was under attack.

And Frank Connor knew who was responsible.

Seated alone in the former linen closet that served as her office, Connor’s assistant hung up the phone and crossed the German’s name off the list of surveillance experts she had prepared for her boss. Suddenly she noticed that her hand was shaking and she put down her pen. Never once in five years had she heard Mr. Connor swear. At all times he’d been respectful, polite, and decent. In her diary she had called him a “nice bloke,” which to a working-class girl was high regard indeed. The outburst had shaken her. But it wasn’t the epithets that left her stunned and feeling weak in the knees; it was the savagery of his tone and the rage in his eyes. For a moment she’d felt certain he was going to harm her. Overcome, she sobbed and rushed to the ladies’ room.

“How many people?” asked Jonathan.

“Seven dead, so far,” said the woman, whose name was Kate Ford, a detective chief inspector for the Metropolitan Police. “Two dozen wounded, several critically. You’re in quite a bit of trouble.”

“Actually, you’re in more than that,” said Graves, who’d introduced himself as being from the counterterrorism wing of MI5. “As it happens, you are currently being viewed as an accomplice to seven counts of murder, as well as conspiracy to commit a terrorist act on British soil.”

Jonathan stared into the hard, expectant faces. He lay in a camp bed with metal rails at his feet, rough sheets, and a green woolen blanket. A portable sphygmomanometer sat near his head, next to an IV drip delivering a clear solution that he guessed to be either glucose or saline into his left arm. There was no television, no second bed. Just a guard at the door dressed in army greens, with a submachine gun hugged to his chest.

From London, Jonathan had been transported in a blacked-out ambulance. He’d ridden alone, except for the company of a police officer who’d told him to “shut it” every time he’d started to ask a question. Ten minutes before arriving, the ambulance had stopped and the driver had come into the rear bay and supervised the draping of a black hood over Jonathan’s head. Only when Jonathan had been installed in his bed had the hood been removed.