The ground was damp here, but it was the only part of the property where the soil was deep enough, without hitting rock. Jarvis settled his cap firmly on his head, spat on his hands, and began to dig. His mind seemed to switch off when he was involved in physical work. It helped him to avoid thinking about things too much.

He had been digging for about half an hour and had built up a good sweat, when he stopped for a moment to wipe his forehead. Across the stream, someone was watching him. The person was partly hidden by the trees, and was given away only by a slight movement. Jarvis stared at the figure for a while, until it slipped away into the woods, back towards the Alder Hall estate.

With a sigh, Jarvis took up his spade and began to dig again. The grave needed to be a bit deeper yet, and the soil was heavy. There was no need for him to call out, or go after the person who had been watching him. He already knew exactly who it was.

‘Well, this is nice,’ said Professor Robertson. ‘And such a surprise. I really hadn’t anticipated an outing this evening. I think I’m going to like you, Detective Constable Cooper. You bring a little excitement into my life.’

The professor stood on the grass between the graves in St Mark’s churchyard. His hands were thrust into the pockets of his coat, as if he was afraid to touch anything. Long strands of hair hung over his ears, flapping in the breeze that blew down from the hillsides above Edendale. Below the church, the River Eden could be seen snaking its way through the town.

‘I’m really sorry to drag you all the way out here, sir,’ said Cooper. ‘But it could be important.’

‘Not at all, not at all. It’s good to get out of the study and away from the books now and then. Very stimulating.’ Robertson nodded, and smiled slyly. ‘Besides, I’m thrilled to get a chance to meet your colleague.’

Behind Cooper, Fry was leaning against a tombstone, listening but saying nothing. He tried to avoid her eye.

‘And these things are actually sarcophagi, you say?’

‘Certainly.’

There were five of them, standing upright against a wall of the church, near the bell tower. Someone had arranged them in descending order, from six feet in length down to one the size of a small child. There were deep cracks in the stone and some of the corners had been sheered off. Pale green lichen had spread across the lower surfaces, like a shroud of cobwebs.