In the wake of the bus, on the opposite pavement, was a single pedestrian: oilskin raincoat, stubby ponytail, two straight lines for eyebrows. Massoudi recognized him instantly. The young man had been at the conference—same row as Hamida but on the opposite side of the auditorium. He’d been sitting in the same seat earlier that morning, when Massoudi had been the lone dissenting voice during a panel discussion on the virtue of barring Israeli academics from European shores.

Massoudi lowered his gaze and kept walking, while his left hand went involuntarily to the shoulder strap of his briefcase. Was he being followed? If so, by whom? MI5 was the most likely explanation. The most likely, he reminded himself, but not the only one. Perhaps the German BND had followed him to London from Bremen. Or perhaps he was under CIA surveillance.

But it was the fourth possibility that made Massoudi’s heart bang suddenly against his rib cage. What if the man was not English, or German, or American at all? What if he worked for an intelligence service that showed little compunction about liquidating its enemies, even on the streets of foreign capitals. An intelligence service with a history of using women as bait. He thought of what Hamida had said to him that afternoon.

“I grew up in Toronto, mostly.”

“And before that?”

“Amman when I was very young. Then a year in Hamburg. I’m a Palestinian, Professor. My home is a suitcase.”

Massoudi made a sudden turn off Woburn Place, into the tangle of side streets of St. Pancras. After a few paces he slowed and looked over his shoulder. The man in the oilskin coat had crossed the street and was following after him.

HE QUICKENED his pace, made a series of turns, left and right. Here a row of mews houses, here a block of flats, here an empty square littered with dead leaves. Massoudi saw little of it. He was trying to keep his orientation. He knew London’s main thoroughfares well enough, but the backstreets were a mystery to him. He threw all tradecraft to the wind and made regular glances over his shoulder. Each glance seemed to find the man a pace or two closer.

He came to an intersection, looked left, and saw traffic rushing along the Euston Road. On the opposite side, he knew, lay King’s Cross and St. Pancras stations. He turned in that direction, then, a few seconds later, glanced over his shoulder. The man had rounded the corner and was coming after him.