‘OK,’ says Cathbad, ‘you win.’

He gets up, rubbing his arms to bring the circulation back. He’s wearing a jacket and a jumper but he’s still cold. He wishes he’d brought his cloak, which – as he’s always telling Nelson – is warm and practical as well as being a symbol of his druidical power. To be honest, he could do with a little of that power right now.

Thing leads him to the foot of the stairs and Cathbad decides to go up and have another look around. There could be an attic somewhere that they had overlooked the first time. The thought of what they might find in such a room sends the first real shivers of fear down his spine.

Cathbad lights another oil lamp. The house is much darker now, the corners have almost disappeared into the shadows, and it’ll be even darker upstairs, where the windows are small. He decides to search thoroughly, looking for clues. What he’s looking for he doesn’t quite know but he knows something is wrong in the little house; just as Thing knows, his nose pressed to Cathbad’s leg, tail between legs; just as Dame Alice knows, although she’s keeping her own counsel.

Cathbad makes a methodical tour of Pendragon’s bedroom, a long, low room with a double bed under the vaulted eaves. Pendragon would have had trouble standing up in here, thinks Cathbad. The bed is neatly made with a patchwork quilt, the bedside table empty apart from a teacup containing mouldy leaves and a book of old ballads. Cathbad opens the oak chest at the foot of the bed. It is full of bed linen, carefully folded with lavender. The wardrobe, jammed under one of the beams, contains a collection of robes as well as some more utilitarian garments, mostly jeans and work shirts. There is nothing else in the room, no bookcase, no photographs, nothing of a personal nature at all. Cathbad glances up at the wooden crucifix on the wall and offers up a quick prayer to Saint Anthony, patron saint of finding things. Help me find Pendragon before it’s too late.

The other two rooms are full of personal stuff. Tea chests full of books, an old bicycle, sundry items of broken furniture, a huge Victorian bird cage, several gloomy old paintings, even a chipped cistern and sink. Pendragon obviously just shuts the door on these rooms and lives in minimalist splendour in the master bedroom. Cathbad is about to go back downstairs when something flashes across his brain, like a subliminal advertising message. There was another door. It was in Pendragon’s bedroom, just by the wardrobe. A low door, half hidden by a curtain. Cathbad turns back, trying to find a calming mantra to slow his heart down.

The door is locked but Cathbad, who has an excellent visual memory, remembers a bunch of keys hanging by the larder in the kitchen. He runs back downstairs, Thing clattering at his side. He spends a few frustrating minutes trying different keys but eventually one – an unobtrusive Yale – fits.

He switches on the light and sees a tiny room, barely six feet wide, containing a desk, office chair and laptop. Cathbad pauses. Something shocking has just happened. What was it? He switched on the light … In a house lit by oil-fired lamps, he has switched on a light. And in front of him is a perfect slice of twenty-first-century life. Desk, laptop, mobile phone, even an iPod in its dock. Shelves hold lever-arch files and a wireless modem twinkles with green lights. It is as if he has gone forward in time, stepped into the wardrobe and discovered a high-tech Narnia. But even as he sits at the desk, he knows that this hidden room can’t mean anything good. Pendragon must have his reasons for hiding his links with the outside world but Cathbad can’t think of any that make him see his old friend in a warm and twinkly light.

He opens the laptop. It asks him for a password and – exercising his psychic powers – he guesses ‘Thing’. The computer flashes into life. The first file he sees is titled White Hand. Cathbad’s heart sinks. He doesn’t want to find out any more. He is about to close the case when something catches his eye, a silver pimple at the side of the screen. A memory stick. He clicks onto the C drive and reads the words ‘Dan’s Computer’.

*

Ruth is on the beach when she gets Cathbad’s message. She felt that Kate deserved some time running about after the library and the cafe. So after a healthy lunch of chips on the pier, they headed down to the sands. As soon as they got there it started to rain and even the donkeys had sought shelter. But Ruth and Kate play on, jumping over puddles and writing in the sand. Kate is wearing a raincoat but Ruth has forgotten to bring hers and soon her hair is hanging in wet ribbons and her feet are soaking in their thin shoes. She takes them off and runs barefoot, enjoying the feeling of the cool sand between her toes. ‘Me too,’ yells Kate, so Ruth takes her shoes off too and they both run, laughing, in and out of the freezing water. For those few moments, Ruth feels that she is completely happy.

The tide comes in incredibly quickly, faster even than on the Saltmarsh. Now, it’s as if the sea is erasing all the frivolities of Blackpool life – the donkeys’ hoof-prints, the writing on the sand (Ruth has read at least two ‘Marry Me’s), the chip wrappers and the half-eaten ice creams. Ruth thinks of an Etchasketch that was given to Kate last Christmas. It was too old for her but Ruth spent many happy hours writing or drawing and then watching as the inexorable line moved across the screen, restoring everything to smooth blankness. The moving finger writes and, having writ, moves on. Eventually, Ruth and Kate are standing on the steps, looking out at an expanse of water. The beach has completely vanished.

Ruth’s phone recalls her to life. She isn’t surprised when she sees that it’s from Cathbad but the words make her stand stock still as the cold North Sea breaks over the step and soaks her feet.

Have found Dan’s laptop. Tell Nelson.

*

As night falls Thing becomes more and more frantic. He keeps going to the front door and barking at the rain. Cathbad lights more oil lamps and tries to start a fire. It is something he’s good at (Nelson once called him a closet arsonist) but today his skills desert him. He kneels by the hearth, crumpled paper in hand, defeated. Thing whines softly in the background.

‘It’s OK, boy,’ says Cathbad. ‘Do you want food? There’s food in the kitchen.’

As he says this he hears Nelson’s voice, those familiar flat northern vowels.

He’s got enough food for a week.

There are several food bowls in the kitchen. Pendragon has left his dog enough food for a week. His friend – the druid who keeps a high-tech office hidden in his bedroom – obviously isn’t expecting to return for some time. But why leave the door unlocked, especially when he has all that expensive equipment upstairs? Cathbad stands still, listening to the house. The ancient beams creak, upstairs something – probably a mouse – is scurrying from room to room. Outside, the rain hammers on the windows as it did the day he came here with Ruth. Did Pendragon know then that Ruth was Dan Golding’s friend? Was that why he seemed so scared when they arrived? A sudden movement makes Cathbad jump but it’s only Thing scratching at the door. The crazy animal evidently wants to go outside. Well, Cathbad believes in following instincts, his own and those of other creatures. Holding the lamp high, he opens the heavy oak door.

Thing runs down the hill. Cathbad follows, more carefully. It’s dark now and the ground is steep. Also it’s raining heavily, turning the earth to mud. Cathbad stumbles. He doesn’t want to break his leg and lie undiscovered for weeks. Also, he doesn’t want to lose the dog.

‘Thing!’ he calls. ‘Thing! Come back!’

He sees a white shape at the bottom of the path and heads towards it. Thing is standing by a small group of trees. Hidden in the trees is a building, taller than it is wide, an outhouse of some kind. Cathbad approaches, driven on now by a sick certainty of disaster. By all the gods in the pantheon, he knows that nothing good lies within.