As he scans the paths criss-crossing the lawn at the front of the house, his eye is immediately drawn to a figure with a pushchair. But it’s not Maeve. It’s a man in a flapping cloak-like jacket with long grey hair in a ponytail. Nelson rubs his eyes. He must be going mad because, for a moment, he thought that the man with the baby was Cathbad.

*

Ribchester is a picturesque town nestling in a bend in the river. Ruth is beginning to realise that Nelson was speaking the truth when he once told her that there were pretty places near Blackpool. Preston isn’t one of them but Lytham is certainly an attractive town and the Pendle Forest – well, if she had nightmares last night about Dame Alice and her familiar, that’s not the fault of the countryside, which was undeniably beautiful. Ribchester is cosier – grey stone houses looking as if they’ve grown there rather than been built, a church, pubs, the winding river – it’s all very English and tranquil.

Clayton Henry parks his car, a sporty red number, behind the church.

‘The church was actually built slap-bang on top of the Roman fort,’ he says, ‘You can see the remains of a granary in the graveyard. The baths are behind one of the pubs. The White Bull.’

As they walk around the town, Ruth begins to realise that the Romans are living side-by-side with modern-day Ribchester. The White Bull has ornate pillars at the front, said to be taken from the Roman fort. Terraced houses have Roman walls in their gardens and the church shares its graveyard with medieval tombs and more recent excavations showing floors and hypocausts.

‘The museum’s next door,’ says Henry, stepping carefully over a gravestone. ‘There are lots of wonderful things there.’

‘The Ribchester helmet?’ asks Ruth, remembering something she once read.

‘A replica,’ says Henry. ‘The original’s in the British Museum.’

He leads the way through a low gate and along a lane overhung with brambles and cow parsley. ‘Dan’s excavations centred on a spot further down the river,’ he says. ‘You don’t mind a short walk, do you?’

Ruth wonders how short a short walk is. She likes walking only in moderation. Something Max and Nelson have in common is that they are always striding off without looking back to see if she is following. One day she won’t be.

She is also worried about getting back to Kate. She rang Cathbad from the university, saying she was going to be longer than she’d thought and he’d been unconcerned. ‘I’ll take Kate out for a bit, explore Lytham,’ he’d said. ‘Take your time.’ Cathbad really is the king of the walkers, covering miles in a day, sometime walking all night, across dark fields and through shuttered towns. He used to be a postman, he explained once, and that taught him the value of exploring places on foot. ‘You see more,’ he says, ‘At eye level.’ Ruth hopes he won’t take Kate too far.

But Clayton Henry does not look like much of a rambler. He looks essentially urban, dressed in a pink shirt and freshly ironed chinos with distinctly unhikerish shoes, pointed and highly polished. Ruth doesn’t imagine that he will drag her miles over fields and stiles. In fact, he seems out of breath by the time they reach the river.

‘Not far now,’ he pants.

The river is obviously on its last lap before the sea, looping extravagantly across the fields, dotted with little islands and crescent-shaped pools. Sheep graze on the flat ground between the loops and, in the distance, Ruth can see a black shape, half lost in the clouds.

‘Is that Pendle Hill?’ she asks, thinking that she knows the answer.

‘Yes,’ says Henry. ‘Have you been up there? There’s a grand view, but it’s a bit spooky, to my mind.’

‘I went there yesterday. I’ve got a friend who lives near Fence.’ She hesitates, aware that ‘friend’ doesn’t really cover her tenuous connection with Pendragon.

‘Sooner him than me,’ says Henry. Ruth thinks it’s interesting that he assumes the friend must be male.

Birds swoop low over the water, reminding Ruth once again of the Saltmarsh. She wonders what this area was like in Roman times. The river would still have been here, though its course may well have changed; it would have been a valuable link in the supply chain, carrying goods inland, and back out to sea towards other parts of the great Empire. When the Roman troops left, the ships would no longer have come into port, laden with wine, olive oil and pottery – that distinctive orangey-red Samian ware found on the site at Swaffham. Was this where Arthur made his last stand, abandoned by Rome, beset on all sides by invading Picts and Celts?

‘Here we are,’ says Henry.

They are on slightly higher ground, a field just outside the wall of the church. The excavation, which is about ten feet across, includes walls and some tesserae, which could have formed part of a mosaic. In one corner a tarpaulin covers what is obviously a deeper hole. Ruth wonders how long ago it was that Dan dug here. The excavation has a lonely look, outside the city walls. Sheep are cropping the grass near the exposed stones.

‘The Roman Road was near here,’ says Henry. ‘Funny how place names survive. There’s a village nearby called Street and the road across the bridge is still called the Roman Road.’

Ruth knows that the word ‘street’ comes from the Latin ‘strata’, meaning layer, and refers to the many layers that went into constructing a Roman road, one of the wonders of that empire.

‘So the temple would have been on the road to the port?’ she says.

‘It looks like that, yes,’ says Henry. ‘There’s another temple at Ribchester with altars dedicated to Apollo and Victory. Just what you’d expect. But Dan thought this was later. Mid to late 400s, he reckoned.’

Ruth looks down at the ancient walls, exposed to the wind and the air. It is generally thought that the Romans left Britain between 383 and 410 AD, which would mean that this temple was built after the withdrawal, in the mysterious world of warring tribes, the battle for the soul of Britain, the beginning of the Dark Ages. It would also fit that, whoever lay in this tomb, he was buried rather than cremated. By the first century AD, cremation was already a thing of the past. Her heart beats faster. A temple, built in the Roman style, dedicated to an unknown god – even without King Arthur, this is a thrilling discovery.

‘The sarcophagus was here,’ says Henry, lifting a corner of the tarpaulin. ‘Buried about six feet down, under the central altar. The lid was broken, but the piece with the inscription remained almost intact.’

‘Where is it now?’ asks Ruth, peering into the trench. She can see the shape of a burial cut into the surrounding soil, a deep rectangular void, and some pieces of heavy stone. Nothing else.

‘At the university,’ says Henry. ‘We have a strong-room there. We would have used it for the bones but we felt they needed … well, special treatment.’ Ruth turns to look at him. She wonders why he is being so shifty about the excavation. Did something go wrong?

‘There were a few other significant finds,’ he says, rather hurriedly. ‘A carving of a raven with the words Bran and Corvus below it, and a great deal of skeletal matter.’

‘Human skeletal matter?’

‘No, avian. It looks as if a number of birds were sacrificed here.’

Offerings to the Raven King, thinks Ruth. She looks around her, at the marshy plain with the wide sky high above. Seagulls are hanging in the air, black against the clouds. If you had to invent a spot for a temple dedicated to a strange pagan bird-deity, this would be the place for it.

Clayton Henry is still looking slightly embarrassed. He stoops down to brush the mud off his cream trousers. Ruth wonders if he is going to change the subject, but even so she is surprised when what he actually says is, ‘Would you like to come to a barbeque at my house on Saturday?’

‘Thanks,’ stammers Ruth. ‘But I’ve got my daughter with me and … and a friend.’