Gabriel looked out his window as Sarah Bancroft floated virtuously past, dressed in a long dark overcoat with a narrow waist. She held a leather briefcase in one hand and a cell phone in the other. Gabriel heard her voice briefly as she passed. Low, sophisticated, a trace of an English accent-a remnant, no doubt, of her time at the Courtauld and a childhood spent in international schools abroad.

“What do you think?” asked Carter.

“I’ll let you know in a minute.”

She came to the corner of Q Street and 20th Street. On the opposite corner was an esplanade filled with sidewalk vendors and a pair of escalators leading to the Dupont Circle Metro station. The traffic light in Sarah’s direction was red. Without stopping she stepped from the curb and started across. When a taxi driver sounded his car horn in protest, she shot him a look that could melt ice and carried on with her conversation. Then she continued slowly across the intersection and stepped onto the down escalator. Gabriel watched with admiration as she sank slowly from view.

“Do you have two more just like her?”

Carter fished a mobile phone from his pocket and dialed. “We’re on,” he said. A moment later a large black Suburban rounded the corner and parked illegally on Q Street adjacent to the escalators. Five minutes after that Gabriel saw her again, this time rising slowly out of the depths of the Metro station. She was no longer speaking into her telephone, nor was she alone. Two of Carter’s agents were with her, a man and a woman, one on each arm, in case she had a sudden change of heart. The back door of the Suburban swung open, and Sarah Bancroft vanished from sight. Carter started the engine and headed back to Georgetown.

THE BLACK SUBURBAN CAME to a stop fifteen minutes later outside a large Federal-style town house on N Street. As Sarah mounted the curved redbrick steps, the door opened suddenly and a figure appeared in the shadows of the portico. He wore creaseless khaki trousers and a corduroy blazer with patches on the elbow. His gaze had a curious clinical detachment that reminded Sarah of the grief counselor she’d seen after Ben’s death. “I’m Carter,” he said, as if the thought had occurred to him suddenly. He didn’t say whether it was his first name or his last, only that it was genuine. “I don’t do funny names anymore,” he said. “I’m Headquarters now.”

He smiled. It was an ersatz smile, like his brief ersatz handshake. He suggested she come inside and once again managed to leave the impression of sudden inspiration. “And you’re Sarah,” he informed her, as he conveyed her down the wide center hall. “Sarah Bancroft, a curator at the well-regarded Phillips Collection. Sarah Bancroft who courageously offered us her services after 9/11 but was turned away and told she wasn’t needed. How’s your father?”

She was taken aback by the sudden change in course. “Do you know my father?”

“Never met him actually. Works for Citicorp, doesn’t he?”

“You know exactly who he works for. Why are you asking about my father?”

“Where is he these days? London? Brussels? Hong Kong?”

“ Paris,” she said. “It’s his last post. He’s retiring next year.”

“And then he’s coming home?”

She shook her head. “He’s staying in Paris. With his new wife. My parents divorced two years ago. My father remarried right away. He’s a time-is-money sort of man.”

“And your mother? Where is she?”

“ Manhattan.”

“See your father much?”

“Holidays. Weddings. The occasional awkward lunch when he’s in town. My parents divorced badly. Everyone took sides, the children included. Why are you asking me these questions? What do you want from-”

“You believe in that?” he asked, cutting her off.

“Believe in what?”

“Taking sides.”

“Depends on the circumstances, I suppose. Is this part of the test? I thought I failed your tests.”

“You did,” said Carter. “With flying colors.”

They entered the sitting room. It was furnished with the formal but anonymous elegance usually reserved for hotel hospitality suites. Carter helped her off with her coat and invited her to sit.

“So why am I back?”

“It’s a fluid world, Sarah. Things change. So tell me something. Under what circumstances do you think it’s right to take sides?”

“I haven’t given it much thought.”

“Sure you have,” Carter said, and Sarah, for the second time, saw her grief counselor, sitting in his floral wingchair with his ceramic mug balanced on his knee, dully prodding her to visit places she’d rather not go. “Come on, Sarah,” Carter was saying. “Give me just one example of when you believe it’s all right to take sides.”

“I believe in right and wrong,” she said, lifting her chin a little. “Which probably explains why I flunked your little tests. Your world is shades of gray. I tend to be a bit too black and white.”

“Is that what your father told you?”

No, she thought, it was Ben who accused her of that failing.

“What’s this all about?” she asked. “Why am I here?”

But Carter was still turning over the implications of her last response. “And what about the terrorists?” he asked, and once again it seemed to Sarah as if the thought had just popped into his head. “That’s what I’m wondering about. How do they fit into Sarah Bancroft’s world of right and wrong? Are they evil, or is their cause legitimate? Are we the innocent victims, or have we brought this calamity upon ourselves? Must we sit back and take it, or do we have the right to resist them with all the force and anger we can muster?”

“I’m an assistant curator at the Phillips Collection,” she said. “Do you really want me to wax lyrical on the morals of counterterrorism?”

“Let’s narrow the focus of our question then. I always find that helpful. Let’s take for an example the man who drove Ben’s plane into the World Trade Center.” Carter paused. “Remind me, Sarah, which plane was Ben on?”

“You know which plane he was on,” she said. “He was on United Flight 175.”

“Which was piloted by…”

“Marwan al-Shehhi.”

“Suppose for a moment that Marwan al-Shehhi had managed somehow to survive. I know it’s crazy, Sarah, but play along with me for argument’s sake. Suppose he managed to make his way back to Afghanistan or Pakistan or some other terrorist sanctuary. Suppose we knew where he was. Should we send the FBI with a warrant for his arrest, or should we deal with him in a more efficient manner? Men in black? Special forces? A Hellfire missile fired from a plane without a pilot?”

“I think you know what I would do to him.”

“Suppose I’m interested in hearing it from your own lips before we go further.”

“The terrorists have declared war on us,” she said. “They’ve attacked our cities, killed our citizens, and tried to disrupt the continuity of our government.”

“So what should be done to them?”

“They should be dealt with harshly.”

“And what does that mean?”

“Men in black. Special forces. A Hellfire missile fired from a plane without a pilot.”

“And what about a man who gives them money? Is he guilty, too? And if so, to what degree?”

“I suppose it depends on whether he knew what the money would be used for.”

“And if he knew damned well what it would be used for?”

“Then he’s as guilty as the man who flew the plane into the building.”

“Would you feel comfortable-indeed justified-in operating against such an individual?”

“I offered to help you five years ago,” she said contentiously. “You told me I wasn’t qualified. You told me I wasn’t suited for this sort of work. And now you want my help?”

Carter appeared unmoved by her protest. Sarah felt a sudden empathy for his wife.

“You offered to help us, and we treated you shabbily. I’m afraid that’s what we do best. I suppose I could go on about how we were wrong. Perhaps I might try to soothe your feelings with an insincere apology. But frankly, Miss Bancroft, there isn’t time.” His voice contained an edge that had been absent before. “So I suppose what I need now is a straight answer. Do you still feel like helping us? Do you want to fight the terrorists, or would you prefer to go on with your life and hope it never happens again?”