They finished their drinks and Lumsden said he had to get back to the station. He gave Rebus his telephone numbers – office and home – and took note of Rebus’s room number.

‘Anything I can do, give me a call,’ he said.

‘Thanks.’

‘You know how to get to T-Bird Oil?’

‘I’ve got a map.’

Lumsden nodded. ‘What about tonight? Fancy going for a meal?’

‘Great.’

‘I’ll drop by about seven-thirty.’

They shook hands again. Rebus watched him leave, then headed back to the bar for a whisky. As advised, he charged it to the room, and took it upstairs. With the curtains closed, the room was cooler but still airless. He looked to see if he could open the windows, but couldn’t. They had to be twelve feet high. With the curtains closed, he lay on the bed and slipped off his shoes, then replayed his conversation with Lumsden. It was something he did, usually finding things he could have said, better ways of saying them. Suddenly he sat up. Lumsden had mentioned T-Bird Oil, but Rebus couldn’t recall telling him the name of the company. Maybe he had … or maybe he’d mentioned it to DC Shanks over the phone, and Shanks had told Lumsden.

He didn’t feel relaxed any more, so prowled the room. In one of the drawers he found material about Aberdeen, tourist stuff, PR stuff. He sat down at the dressing table and started to go through it. The facts came with a zealot’s force.

Fifty thousand people in the Grampian region worked in the oil and gas industry, twenty per cent of total employment. Since the early seventies, the area’s population had increased by sixty thousand, housing stock had increased by a third, creating major new suburbs around Aberdeen. A thousand acres of industrial land had been developed around the city. Aberdeen Airport had seen a tenfold increase in passenger numbers, and was now the world’s busiest heliport. There wasn’t a negative comment anywhere in the literature, except for the minor mention of a fishing village called Old Torry, which had been granted its charter three years after Columbus landed in America. When oil came to the north-east, Old Torry was flattened to make way for a Shell supply base. Rebus raised his glass and toasted the memory of the village.

He showered, changed his clothes, and headed back to the bar. A flustered-looking woman in long tartan skirt and white blouse came bustling up to him.

‘Are you with the convention?’

He shook his head, and remembered reading about it: pollution in the North Sea or something. Eventually the woman shepherded three corpulent businessmen out of the hotel. Rebus went into the lobby and watched a limo take them away. He checked his watch. Time to go.

Finding Dyce was easy, he just followed signs to the airport. Sure enough, he saw helicopters in the sky. The area around the airport was a mix of farming land, new hotels, and industrial complexes. T-Bird Oil had its headquarters in a modest three-storey hexagon, most of it smoked glass. There was a car park at the front, and landscaped gardens with a path meandering through them to the building itself. In the distance, light aircraft were taking off and landing.