At the ladder, he lowered the evidence bags first before roping her to him. ‘I’ll go first,’ he said. ‘Just look straight ahead, not down.’

Their descent passed in a blur, much like when she’d abseiled down Kilt Rock on Skye, the difference being she didn’t land on solid ground this time, but on the rocking police launch. There was a brief welcome from the pilot, then they were slicing through the waves towards the Houton slipway.

‘I’ll take the evidence through to the station,’ Erling told her as they parted on the jetty. ‘It’ll go down with you tomorrow.’

Stepping into the solid stone of Magnus’s house, Rhona said a silent thank you to whatever Norse god had seen her safely back.

Magnus, working in his study, came out to greet her. ‘You’ve had a couple of phone calls,’ he said. ‘They tried me when they couldn’t reach you.’

‘Who?’ Rhona said, hoping one caller might have been McNab.

‘Check your mobile.’

Reaching her room, Rhona did exactly that. There were, in fact, three messages. One from Chrissy demanding Rhona call her, one from Bill asking the same.

The third wasn’t from McNab, but from Ava Clouston.

I need to speak to you alone. Can you come to the farm. Now.

50

The rain was on in earnest. Driven by the wind, it splattered the windshield so insistently that Rhona had to slow to a crawl to spot the track down to the Clouston farm. Untarred, the route was already puddled and muddy.

She could see the house lights in the distance, the Flow beyond, the distant hills of Hoy looming through the rain. Although still daylight, the scudding dark rain clouds made it seem more like dusk.

She’d stopped registering the presence of the Orlova. Perhaps because its ghostly shape felt more threatening than the dark sky, the wind or the rain.

Approaching the farmhouse, she found a long stone building, two-storey, with three attic windows facing the sea. Between the house and Scapa Flow stood a cluster of farm buildings, the largest, probably the byre, the furthest away. Nearest the shore was what looked like a small boathouse.

As she pulled up in front of the house, Ava appeared at the front door to welcome her in.

The kitchen was bright and warm, a laptop open on the kitchen table. Alongside the range was a dog basket lined with a tartan blanket.

‘You have a dog?’ Rhona said.

‘Finn. He’s down at the boathouse with Dougie.’

‘They’re not going out in a boat in this weather?’ Rhona said.

Ava shook her head. ‘Dougie likes to spend time on the Fear Not, whatever the weather. Can I get you a tea or a coffee?’ she offered, waving Rhona to a seat at the table.

‘Coffee, please,’ Rhona said.