How had Dan – urban, sophisticated Dan – fitted in here? Perhaps Fleetwood, where he lived, is a bijou artists’ quarter, full of antique shops and espresso bars. But he must still have driven in to Preston every day, past these depressed estates and cheerless parades. Dan, whose parents lived in an elegant town house, each floor crammed with books (Ruth went to a party there once when Dan’s parents were away). Dan, who sometimes wore a dinner jacket over jeans and knew the right way to eat asparagus. How had he coped with a place where the only cafe offers chips with prawn cocktail sauce? Well, maybe his colleagues were brilliant, witty sophisticates. And of course it was here, in the ‘frozen and inhospitable north’ that Dan had made his great find. That would have made up for anything.

The directions seem clear enough but Ruth gets lost several times, driving into deserted industrial estates and dead-end streets. She stops once to ask the way but she picks a man who doesn’t understand her and clearly thinks she’s rather frightening. At any rate, he backs away before she can finish her sentence. Ruth turns the map upside down, performs a thirty-point turn and retraces her steps. Surely a university would be hard to miss? She drives down another side road and sees a grim industrial building with the words ‘Sickers Tobacco’ painted in vast white letters on one of the walls. This can’t be it, can it? It is. A small sign welcomes visitors to ‘Pendle University: A new way of learning’. Ruth learns later that the students’ nickname for the place is ‘The Fag Factory’.

Inside, the reception desk sits uncomfortably in a cavernous space, three storeys high. It looks like a prison, thinks Ruth; it even has those inner balconies running round the central atrium, linked by flights of wroughtiron stairs. All it needs is a suicide net. Ruth asks for Clayton Henry, thinking again how odd the name sounds. The receptionist, too, seems to find it strange.

‘Who?’ she asks, manoeuvring her chewing gum to the other side of her mouth.

‘Clayton Henry.’

‘What department?’

‘Archaeology.’

‘We haven’t got an archaeology department.’

Ruth stares at her. For one moment she thinks she has imagined the whole thing – Dan dying, Clayton’s invitation, the Raven King, the lot. But Andrea Vickers had seemed to know Clayton Henry quite well (‘He’s quite a character’) and Ruth has an email from him, with directions, printed out in her pocket.

This last provides the clue. At the bottom of the email are the words ‘History Department’. The receptionist reluctantly concedes that such a department exists and puts through a call. ‘Mr Henry? Visitor for you.’ She then puts down the phone and goes back to her gum, ignoring Ruth altogether.

There is nothing Ruth can do but wait, hoping the message got through to someone. She walks around the atrium which is decorated – if that is the word – by posters advertising the work of the engineering and chemistry departments. Underground piping, laboratories, men in hard hats, women in white coats. There is no sign that anything as effete as history – much less archaeology – is even taught here.

‘Ruth!’ A figure is scurrying down one of the iron staircases. Ruth looks up to see a smallish, plumpish man coming towards her, both hands outstretched.

‘Mr Henry?’ she says.

‘Clayton. Please.’ He takes her hand in both of his. For one horrible moment she thinks he might be about to kiss her. ‘So good of you to come.’

‘That’s OK.’ Ruth extricates her hand.

‘How do you like Andrea’s cottage?’

‘It’s lovely,’ says Ruth. ‘Lytham’s very pretty.’

‘Lytham? I’ve seen Stone Age burial mounds that are livelier than Lytham.’ He laughs heartily. Ruth smiles. She is surprised to hear him use the term ‘Stone Age’. An archaeologist would usually distinguish between Palaeolithic (old Stone Age), Mesolithic (middle) and Neolithic (new). She begins to suspect that Clayton Henry is not an archaeologist.

And once they are sitting in his cramped fourth-floor office she finds that her suspicions are correct. Clayton Henry is a historian, and head of a department that includes archaeology and anthropology as well as sociology and classical studies. Dan Golding, described by Henry as ‘one of our archaeologists’, was, in fact, their only archaeologist. ‘It’s only a module, you see,’ said Clayton Henry apologetically. ‘Not many people opt for it because it’s very demanding. Funnily enough, we’re thinking of changing the name to “forensic archaeology”. Kids go for anything with “forensic” in the title these days. Especially the girls.’

Ruth, a forensic archaeologist to her fingertips, looks disapproving. Forensic archaeology is a discipline in itself, not just a phrase to appeal to teenage girls who enjoy watching Silent Witness.

This explains, of course, why Henry was so keen to get Ruth up to Lancashire. It’s not so much a question of her being better than anyone in-house – there is no one else in-house. Ruth feels self-satisfaction seeping out of her. And Dan – not only was he an archaeologist in an obscure university, he was the only archaeologist in an obscure university. What had happened to her brilliant friend?

Clayton Henry puts on a concerned face to talk about Dan. ‘Such a tragedy. A lovely man. We’re all devastated. Did you know the family well?’

‘Dan and I were at university together,’ says Ruth. She feels uncomfortable discussing Dan with this stranger whose sad voice does not match his curious eyes. Besides, the Dan she knew was not Dan Golding, lone archaeologist at a university that used to be a cigarette factory, but Dan the Man, the piano-playing, Pernod-drinking student.

‘I never really knew his family,’ she says. ‘They must be in shock. It was such a terrible way to die.’

‘Yes, indeed,’ Henry allows his voice to fade away respectfully before launching, with evident relief, into the next topic.

‘Did Dan tell you anything about his discovery?’ he asks.

‘No,’ says Ruth. For reasons she has not explored, even with herself, she doesn’t want to discuss the letter, or its disturbing echoes, with Clayton Henry.

‘Well …’ Is it her imagination or does the head of department relax a little? ‘As I’m sure you know, there was a significant Roman settlement at Ribchester, not far from here.’

‘I’ve read about it,’ says Ruth guardedly.

‘Well, Dan’s excavations centred on a location a little way outside Ribchester,’ says Henry, settling cosily in his chair. ‘He was convinced that he had found the site of a temple dedicated to a god who was at once Celtic and Roman. That’s not uncommon, you know.’

‘I know,’ says Ruth.

‘Well, the really exciting find was under the temple altar.’ He pauses, enjoying the moment. ‘A stone sarcophagus containing human remains. The remains, Dan was sure, of a very important military man.’

‘What made him think that?’ asks Ruth, although she can guess.

‘The body was buried with ceremony, within the temple itself, and with funerary goods,’ says Henry. ‘But the really significant thing was the inscription on the tomb. Rex Arthurus. Britannorum Rex.’

He looks expectantly at Ruth, who is frantically working out the Latin. She wishes Max were here to translate it.

‘King Arthur,’ she says at last. ‘King of Britain.’

‘King of the Britons,’ corrects Henry.

There is a silence. In the distance, Ruth can hear somebody hoovering. Of course, it’s the holidays; there will be no students, only cleaners.

‘Did Dan really think it was King Arthur?’ asks Ruth. ‘The King Arthur?’

‘What do we mean by the King Arthur?’ asks Henry, sounding like a typical historian. ‘There are so many legends, very few historical facts. Documentary evidence for the post-Roman period is scarce. Arthur’s not even mentioned in The Anglo-Saxon Chronicle, for instance. Geoffrey of Monmouth writes about him in his Historia Regum Britanniae but that’s a very dodgy historical source, full of mythology and sheer imagination. There’s also a ninth-century Latin source, the Historia Brittonum. That depicts Arthur as a Romano-British king who unites the warring British tribes after the departure of the Romans. The Welsh Annals link Arthur to the Battle of Badon in about 516 AD. The dating of the temple would tie in with this. One interesting thing, though, neither the Historia nor the Annals uses the word “Rex” to describe Arthur. That would make our inscription unique.’