It took Emma exactly thirty minutes to reach her destination. Her route took her south, back through Hampstead to Bayswater Road, where she cut through Hyde Park toward St. James. She drove slowly, more cautiously than was her habit. His Emma-or the real Emma, as he liked to think of her-was an Indy car driver in search of a track. She had only two speeds, fast and faster. This one braked for yellow lights instead of flooring it to make it through, signaled religiously, and rarely changed lanes. The implication was clear. Operational Emma, or Nightingale, could not afford to be stopped by the police.

From St. James it was a maze of narrow residential streets, constantly turning left, then right, but always keeping toward the Thames. Afraid to be seen, Jonathan shouted for the driver to lag behind, and two or three times they lost all sight of her. Luck, however, was with them, and after a tortured span of five or ten seconds, they spotted her again.

She parked in a space on Storey’s Gate Road. It was a narrow two-way street bordered by attached buildings dating from the late nineteenth century. All were five stories high, hewn from an identical batch of gray Portland cement, and constructed as part of a single ambitious project to gentrify the area. Only afterward did Jonathan remark on the perfect timing of the departing motorist, or recall that the car pulling out of the space had been a Vauxhall, the same car mentioned by code in the text message on Emma’s phone. At that moment, he simply attributed it to Emma’s good fortune.

“What now?” asked the cabbie as they stared at the BMW from a distance of a hundred meters. Emma’s silhouette was distinctly visible. She sat behind the wheel, as stationary as a statue.

“We wait,” said Jonathan.

It was past seven a.m. when Kate Ford returned home and closed the kitchen door behind her. “Good Lord!” she muttered as the scent of spoiled milk assaulted her senses. She flipped on the light and immediately identified the culprits: a bowl of half-eaten muesli and a quart of milk stood on the table exactly where she’d left them some twenty-six hours earlier. In her rush to get to One Park, she’d forgotten to clean up after herself.

Hurriedly she flung open the windows and waved the foul-smelling air out. Unlike Lord Robert Russell, she did not enjoy the benefits of central air conditioning. East Finchley was much farther from Park Lane than 20 map kilometers. Sighing, she dumped the cereal down the sink and followed it with the clotted milk. It was not how she’d envisioned coming home after her first day back on the job.

Upstairs, she turned on the shower. When it grew hot, she undressed and threw her suit and blouse into a pile on the floor. It was off to the dry cleaner for both. She didn’t like the idea of paying ten quid to have them cleaned and pressed, but she liked the idea of not smelling to high heaven. She took care climbing into the tub. The water was hot and the pressure was strong enough to peel paint, which was how she liked it. She washed her hair, then soaped her body, running a loofah over her arms and legs. She was careful to avoid the scar above her hip. A few weeks earlier, when she’d first come home from hospital, it had bulged like a swollen leech. The bullet had entered from the rear, just above the spleen, leaving barely a clean hole, and then blasted through the other side like a sledgehammer through rotting wood. Hollowpoints did that. The doctors had been unanimous in pointing out that it was a miracle that the splintered round had not nicked an artery or caused greater internal damage.

Kate remained under the showerhead until every last drop of warmth had been bled and the nozzle ran as cold as a Scottish stream. And then she stayed longer. She stood beneath the jets until her skin prickled with goose bumps and her flesh went numb. The numbness helped her deal with the silence. If she was frantic to towel herself dry, she didn’t notice that there was no radio blaring, no clumsy male hands clanking the breakfast plates, no East End baritone ordering her to hightail it to the car so they could drive in to work together.

A mirror hung on the wall, and she caught sight of her body, thinner now than it had ever been. She stared at her biceps, which looked taut and ropey beneath her pale skin, at her pelvis, so sharp and fragile, and at her scar. “The bullet destroyed one of your ovaries,” the surgeon had explained with maddening sympathy. “It also tore the lining of the uterus. To control the bleeding, we had to remove the uterus in toto. I’m so sorry. We did everything we could.”

He’d never mentioned the baby, though surely he’d known. Six weeks along was hardly enough for it to show. Maybe he’d been waiting for her to ask. Or maybe he thought Kate didn’t know herself and hoped to save her further anguish. She never knew if it was a boy or a girl.

She touched the scar and felt a jab inside of her, sharp as a spear. Gasping, she caught her eye and stared at the frightened woman bent double in the mirror. Cry, she told the reflection. No one can see you. You’ve been strong. You don’t have to prove how tough you are. It’s time.

The pain went away. Kate stood up straight. Dry-eyed, she turned away from the mirror and wrapped the towel around her.

Someone was knocking at the back door.

Still in her towel, Kate hurried downstairs and ducked a head into the kitchen. She was surprised to find a tall, fair-skinned man in a dark suit standing there with his hands in his pockets, as if he belonged there. “I think your milk’s gone bad,” he said.

“Who the hell are you?”

“ Graves. Five. I apologize for letting myself in. I’d been knocking awhile, and I was afraid that your neighbors were getting curious.”

“Five” for MI5, the country’s national security and counterterrorism apparatus, better known as the Security Service. She should have known it by his posture. He looked as if he had a steel rod in place of a spine.

“What branch?”

“G Branch.” G Branch handled counterterrorism in all countries except Northern Ireland. Kate peered out the front window. The curb in front of her home was empty. “Where’s the blue Rover?” she asked on a hunch, remembering the car that had been parked inside police tape at 1 Park Lane yesterday morning.

“Parked it down the road. Think you might like to get dressed? They’re waiting for us at HQ. Traffic’s a bugger this time of day.”

Kate took a longer look at the man who’d let himself into her home. He was fortyish, tall and spare, with thick blond hair cut more casually than she would have expected. He wore a navy pinstripe, clearly Savile Row, with the requisite inch of cuff showing, and a striped necktie that hinted at service in some elite outfit or another. His black wingtips were of the sleekest order and polished to a paratrooper’s exacting standards. But it was his eyes that captured her attention. They were diamond blue and near holy in their intensity. They were the same eyes she’d seen yesterday evening gazing at her from the offices of Oxford Analytica.

“You have a first name, Mr. Graves?”

“Yeah,” he said. “Colonel.”

MI5 has its headquarters in Thames House, an imposing block-long building situated (as to be expected by the name) on the banks of the River Thames in the Millbank section of London, overlooking Lambeth Bridge. Graves ’s office was on the first floor, down the hall from the director. Kate, the born striver, was suitably impressed. It was a corner office, decorated with fashionable modern furniture. Picture windows offered a stunning view over the south side of the river.