Ahead of them was a drystone circle with a gap in the side. A skua, which seemed to Polly as big as an eagle, suddenly dived at them straight from the sun. Polly shrieked. She could feel the air of its wing-beat on her face. Caroline gave a little laugh. ‘It’s only protecting its nest. If you put your hand in the air, it’ll aim for that and miss your face.’ She pointed at the stone circle. ‘That’s a planticrub. People used to grow cabbages in there as food for the sheep. I suppose the wall sheltered the plants from the salt wind.’

She was about to walk on and Polly could see that her friend had made the decision that this would be her home. She was buying into the history and the culture already. But Caroline’s subject was human geography, and Polly thought she’d always be an outsider here, an observer. She’d regard her neighbours with the same amused objectivity as when she was studying migrant workers for her PhD.

Polly couldn’t imagine life in the city without her friends. Because they’d always been there, she’d never felt the need to build a wider social circle and somehow, at this moment, Marcus didn’t matter. The shock of the diving bird had provoked a panic that was unlike anything she’d experienced in everyday life. At work she was a competent professional, choosing stock for the private subscription library where she worked, advising the historians and students who used it. But here the faintness of the day before had returned. She bent, rested her hands on her knees and felt the blood come back to her head.

‘Do you want to rest for a bit?’ Caroline was solicitous, but smug too. She was fit and she could have continued walking for miles. Polly thought again with surprise that the woman had no real concern for Eleanor’s safety. Her head was full of her new husband and her plans for the future.

They sat with their backs to the wall. The sun had heated the stones and they were out of the wind.

Polly felt herself falling asleep again and wondered how she could do that when Eleanor still hadn’t been found. She stood up, shaking her limbs to feel more awake, and for the first time looked into the planticrub. No sign that anything had been grown there for years. Cropped grass and a scattering of sheep droppings. And an iPhone with a distinctive pink case, which Polly recognized as Eleanor’s.

Chapter Five

Jimmy Perez could sense the tension of the man walking beside him. He seemed rigid, like a robot. Each footstep was heavy and, looking back over the sand, Perez was surprised that their prints weren’t very different, that the ones left by Ian Longstaff were no deeper than his.

‘You’ve been married for three years?’ Here on the beach they could be miles away from the tasteful holiday house of Sletts; Perez felt they were contained in a bubble formed by the natural sounds. There was a breeze blowing from Norway and the tide was sucking on a bank of shingle close to the water. A faint heat haze blurred the distant horizon.