He wasn’t like her. He was nothing like her at all. And yet here she was sharing her free time with him. Here she was letting him turn that free time into yet more work.

She picked up another of the map books, Handy Road Atlas Scotland. The first page, square B4 was the Isle of Man. This really annoyed her for some reason: the Isle of Man wasn’t even in Scotland! The next page, B4 was in the Yorkshire Dales.

‘Bloody hell,’ she said out loud.

‘What is it?’

‘This map, it’s like Bonnie Prince Charlie won the war.’ She flipped to the next page, where B4 was the Mull of Kintyre, but the page after that her eyes fixed on the words ‘Loch Fell’. She studied the square more closely: the M74 motorway and the town of Moffat. She knew Moffat: a picture-postcard place with at least one good hotel, where she’d stopped once for lunch. At the top of square B4 she saw a small triangle, indicating a peak. The peak was called Hart Fell. It was eight hundred and eight metres high. She looked at Hood.

‘A hart’s a kind of deer, isn’t it?’

He got up off the floor, came and sat next to her. ‘Harts and hinds,’ he said. ‘The hart is the male.’

‘Why not a stag?’

‘Harts are older, I think.’ He studied the map, his shoulder touching Siobhan’s arm. She tried not to flinch, but it was hard work. ‘Christ,’ he said, ‘it’s the middle of nowhere.’

‘Maybe it’s coincidence,’ she suggested.

He nodded, but she could see he was convinced. ‘Square B4,’ he said. ‘A fell is another name for a law. A hart is a kind of deer …’ He looked at her and shook his head. ‘No coincidence.’

Siobhan switched her TV on and pressed for Teletext.

‘What are you doing?’ Hood asked.

‘Checking the weather for tomorrow. No way I’m climbing Hart Fell in a gale.’

Rebus had dropped into St Leonard’s, gathered together the notes on the four cases: Glasgow, Dunfermline, Perth and Nairn.

‘All right, sir?’ one of the uniforms had asked.

‘Why shouldn’t I be?’

He’d had a few drinks, so what? Didn’t make him incapable. The taxi was waiting for him outside. Five minutes later, he was climbing the stairs to his flat. Another five after that, he was smoking a cigarette, drinking tea, and opening the first file. He sat in his chair by the window, his little oasis in the midst of chaos. He could hear a siren in the distance; sounded like an ambulance, hurtling along Melville Drive. He had photos of the four victims, culled from newspapers. They smiled at him in black and white. The snatch of poetry came back to him, and he knew all four shared the same characteristic.

They’d died because they’d been available.