There was nowhere Zelda could be completely free of passersby, so she chose a dark spot far enough away from any restaurant or bar—and, as far as she could tell, CCTV—and crossed the stretch of grass that separated the path from the wall. There was no one else standing near her, and the path was now a good ten or twelve feet behind. She leaned her elbows on the wall as if contemplating the view. The tide was well in and the water just below her swirled black and oily. Some of the windows in the office buildings across the river were still lit up, and she could see the occasional silhouettes of late workers walking about in the offices. But they were too far away to see what she was doing.

When there were no boats passing in front of her and no one behind, she slipped the box of knives out of her bag and dropped it over the side. It made a satisfying plop, and she felt a sense of relief, seeing it go down, as if by getting rid of the weapon she had shed some of the burden of the crime.

Just then, she heard a voice behind. “Is everything all right?”

She turned sharply, hand on her heart and saw a young man in jogging gear standing on the grass in front of her.

“Only you were looking a bit lost,” he said, sounding less sure of himself now he could see her at least partially in the city darkness.

“I’m fine,” Zelda said, dredging up a polite smile.

“It’s just . . . you know, sometimes people . . . I don’t mean to be . . .”

“Honest. I’m fine,” Zelda reassured him. “I wasn’t thinking of jumping. I was just enjoying the peace and the view.”

“Oh. I’m sorry I interrupted you, then, if everything’s OK.”

“It’s fine, really. I’m going now, anyway.”

The young man studied her for a moment, as if to make sure she was telling the truth, then he nodded and set off jogging along the path again. Her heart still pounding, Zelda made her way back to her hotel room.

BANKS STOOD at the front door watching the car churn up gravel as it headed down the drive. When the sound of the motor faded, there was silence except for Gratly Beck. It was a warm evening—perhaps the warmest of the year so far—and Banks realized it had been a long time since he had sat by the terraced falls and enjoyed a nightcap al fresco. It was already dark, a clear night, with stars glittering in the sky, so he went back for his wine, then climbed the wall and sat on the grassy bank of Gratly Beck by the terraced waterfalls, looking down on the lights of Helmthorpe in the valley bottom.