Kelly could tell that Rob was mesmerised by the place. It was the same for most people when they first saw it. He was having difficulty separating his own reaction to the stones from the case, and Carla Rigg’s motivation. It was easily done. That’s why she’d brought him here, to witness the power of the place, even though it might have nothing to do with their investigation, if there was one. If Carla Rigg didn’t turn up and they had no forensic match on her, then she’d stay disappeared. ‘You see that peak over there?’ she asked.

‘Blencathra?’ Rob asked. The majestic ridge of Blencathra sat on the northern edge of the National Park and looked like a sleeping feline. Just below that was the ancient settlement of Threlkeld. Opposite that, on the other side of the valley, now occupied by the A66, the Helvellyn range of mountains began, and the first and smallest of those was Threlkeld Knotts.

‘During autumn, at a specific time every year, the sun rises directly over the Threlkeld Knotts, it’s pretty stunning, you should see it.’

‘How do you know that?’ Rob asked.

‘My dad used to bring me. He did tell me when it was but I forgot a long time ago.’ Kelly stopped and looked away towards the west. The man she’d thought of as her father, John Porter, was the person responsible for her love of the fells and her mastery of the sport of conquering them. Her breath caught in her throat and she coughed. She loved him like a father, because that’s what he’d been. She’d only found out about her biological father recently. It took nothing away from John Porter, who’d never known that Kelly wasn’t his. He’d raised her, sat with her when she had a temperature in the night, put calamine lotion on her chicken pox, taken her to watch rugby matches on his moped, taught her how to gut a fish properly, and kissed her before her prom.

The fact that an illicit affair had produced a set of cells not of John Porter wasn’t her concern. But the future was different to what she expected. She now had another man in her life, who also didn’t know that he had a third daughter until last year. She turned back to Rob.

‘That’s not all. On the summer solstice, this stone,’ she paused and walked to the tallest stone in the circle. It was probably eleven feet tall and weighed fifteen tonnes. ‘This casts a shadow a half a mile long.’

‘It’s like a big clock,’ Rob said.

‘Indeed. That’s what all these circles do: tell the time along ancient and astrological parameters.’