'What for?'

'I was at Greenham Common.'

'Ah.'

'I was part of the women's peace camp in the eighties. The cruise missile protest.'

'I remember. Well, I say 'remember"; I was quite young then.'

'December 1983, it was. Difficult to think it's nearly thirty years ago. Fifty thousand of us joined hands and made a circle round the nuclear missile base. We cut through the fences, and some of us got arrested. I was at Yellow Gate.'

'Interesting times.'

'Interesting? You can't imagine the living conditions. We were outside in all kinds of weather. Cold, snow, rain, with no electricity and no running water. Frequent evictions, attacks by vigilantes. But we gave up comfort for commitment. We stopped nuclear convoys, disrupted their training exercises. Though it was non-violent direct action, a lot of women were arrested, taken to court and even sent to prison.'

'What about you? You didn't go to prison, did you?'

'No. I just got a fine and a ticking-off. I didn't take much notice. None of us did.'

Cooper drank some of his tea. It was horrible, and the milk tasted slightly off. But you had to be polite.

'We still haven't found any clue as to why Aidan Merritt was at the Light House on the day he was killed,' he said.

'I'm sorry. I wish I could help.'

'He talked to you about things, though, didn't he?' persisted Cooper.

'Yes, I did know there was something on his mind.'

'You did?'

'But he was all secretive about it. He said there was something he had to do. It was his moral duty.'

'But he didn't tell you what it was?'

'No, not him. He just sort of put his finger to his lips, and winked and nodded. If I'd been sitting next to him, I reckon he would have nudged me in the ribs. He gave the impression I ought to understand what he meant without him having to spell it out. I don't know what it was with Aidan. He'd read too many spy stories, perhaps. Thought he was George Smiley or something.'

Cooper thought it was interesting that Mrs Wheatcroft had referred to George Smiley when most people might have been expected to mention James Bond. It suggested she'd read a few Cold War spy novels himself. John le Carre, at least. If Diane Fry had been here, she wouldn't have noticed that. She wasn't much of a reader.

Mrs Wheatcroft eyed him curiously. He could practically see her mind working, trying to figure something out for herself.

'Didn't Aidan tell anyone else what he was doing?' she said.

Cooper decided to let her in on a bit of information. He felt sure it couldn't do any harm in this case.

'He phoned his wife, Samantha, and left a message. But she couldn't make any sense of what he was saying. It was something about the ninth circle of h.e.l.l.'

'Ah,' she said. 'Dante's Inferno.'

'Of course. Dante's Inferno,' repeated Cooper. 'Yes, you're right. He was there while the moor was on fire, you see.

'The fires, yes. I know about them. Was that it?'

Mrs Wheatcroft watched him silently for a while, until Cooper began to feel uncomfortable under her expectant gaze. There had been a teacher just like her years ago, when he was at school. She had never needed to shout or raise her voice to get his attention. All she had to do was look at him in that way, and it forced him to cudgel his brain for the correct answer, the one she was hoping for.

But this time he seemed to have failed. Mrs Wheatcroft's expression turned to disappointment. A moment later, she changed the subject.

'I heard they found some old mine buildings on the moor,' she said.

'You hear a lot of things,' said Cooper. 'But yes, you're right.'

'Aidan's father was interested in the old mines.'

'Was he?'

'He pa.s.sed away recently, old Charlie Merritt. I suppose that might have been something else Aidan was depressed about. Charlie was a member of the local society.'

'You mean the Mines Historical Society?'

'That's it. He did some research for them, I think. Helped out with mapping the sites around the moors here. There were a lot of them at one time, you know.'

'Yes, I know.'

'Charlie Merritt always said there were some abandoned mines that no one had ever found. They just got lost, and then the heather and bracken grew over them.'

'Did he mention any locations in particular?'

Mrs Wheatcroft shook her head. 'Not to me. He was pretty vague. I suppose we just thought he liked telling stories.'

'What kind of stories?'

'Oh, about the superst.i.tions the old lead miners had. And he liked to tell tales about children who fell down mine shafts years ago and got killed. They are all superst.i.tions, aren't they?'

Cooper put his cup down half finished, hoping Mrs Wheatcroft wouldn't notice until after he'd gone.

'I can't answer about the superst.i.tions,' he said. 'But his stories about the children were probably true.'

When he got back into his car, Cooper sat for a few minutes before driving away, thinking about Mrs Wheatcroft's remarks on mining superst.i.tions and Charlie Merritt's knowledge of the mines. Why had she mentioned that? Was there some connection that existed only in the old lady's mind?

He knew that a few mining enthusiasts still kept one peculiar Peak District practice alive. On Christmas Eve they went down into an old lead mine to light a candle as a tribute to T'owd Mon. It could be difficult to explain the concept to outsiders. It wasn't a specific old man, though it could sometimes refer to an unknown long-dead miner, or to entire previous generations of miners. In other cases, it was a reference to the actual mine workings.

Miners looked on T'owd Mon as a kind of collective spirit, an embodiment both of their predecessors and of the mines themselves. It had been their custom before finishing work on Christmas Eve to leave a burning candle on a good piece of ore as a tribute.

That ongoing connection with history was very strong in the Peak District. Cooper thought it was related to the fact that so much of the area's heritage was visible right there in the landscape, from the Neolithic stone circles and Iron Age hill forts to the mounds and shafts of the abandoned mines, all the way through to remnants of a more recent industrial past.

Cooper started the engine and put the car into gear.

Yes, when you could see it and touch it and smell, it ceased to be history. You were part of it then. In many ways, it became your present.

Naylor and Gullick had been reinterviewed by Carol Villiers and Luke Irvine, and they were all getting exhausted.

'They're like the pair of figures in one of those little wooden weather houses,' said Villiers when they came out for a break.

'How do you mean?' asked Cooper.

'You know the kind of thing, where you get a sort of Jack and Jill in Bavarian costume, the woman coming out when it's sunny, the man only when it rains. They're always in and out, turn and turn about. But nothing really changes. It's too predictable.'

'Their stories tally?'

'In every respect,' said Villiers. 'They seem well rehea.r.s.ed to me. Too confident.'

'Most people can't keep up a story for ever, if you keep asking them questions.'

'These two do.'

'Did you ask them what they were doing at the Light House the day after the Pearsons went missing, when the pub was closed for Christmas?' asked Cooper.

'Of course. They say they went up there out of curiosity. They saw all the activity and went to find out what was going on.'

'And that story was consistent too?'

'I'm afraid so, Ben.'

'That's a nuisance,' said Cooper with feeling.

'Sorry.'

'It's not your fault.'

Villiers glanced at her notebook. 'Gullick's alibi for the time of Merritt's death checks out. So does Naylor's. He was working on a job here in Edendale, laying a patio for someone who lives in Buxton Road. It took him and his mate all day.'

'And the pickup?'

'It was parked on the drive at the house, except for when Naylor's workmate went for their fish and chips at lunchtime. It's been examined. There's no sign of any recent damage, so it can't have been Naylor's vehicle that pushed you off the road.'

In the CID room, Cooper's desk was covered in files and reports. He pushed them to one side and surveyed his team. This was the way it always was in a complex inquiry a one step forward and two steps back.

'Anyway, it seems that Aidan Merritt was visiting Mrs Wheatcroft,' he said.

'The old biddy. What did you call her, Ben? The first Mrs Rochester?'

'That's her.'

'But surely they weren't ...?'

'No. He visited her because she was lonely. Simple as that. Mrs Wheatcroft's husband died years ago, and her family rarely visit. That's why she used to spend time at the Light House. She'd worked there as a waitress or barmaid at one time. She felt she knew people, which she doesn't here in Edendale.'

'I always thought it must have taken a lot of effort for her to get up there and back for a drink when there are lots of pubs nearer to where she lives.'

'Yes. It was never about the drink; it was the place and the people. Since the Light House closed, Aidan has been visiting her once or twice a week, just to sit with her and have a cup of tea. He called in at her house on his way home from school.'

'Still, it's a bit odd.'

'Is it?'

'It's not as if she's related to him or anything.'

'True.'

'And you mean to say he never told his wife what he was up to? Why not, if he was just doing a good turn for an old lady?'

'Perhaps he was embarra.s.sed about it. You just said yourself it seemed a bit odd. A lot of people thought Aidan Merritt was odd already. Ian Gullick and his pals would have laughed at him.'

'There's one other thing,' said Villiers.

'Yes?'

'I remember you saying that it all seemed planned, that the delay in a search getting under way for the Pearsons had been worked out, as if someone knew what the police response would be.'

'Yes.'

'Well, who would have been in a better position to know that than a police officer?' she said. She looked round the group, seeming to enjoy their shocked expressions for a moment. 'Or a former police officer.'

'Maurice Wharton?'

'Yes.'

'You think he masterminded the whole thing?'

'I think some of his regular customers looked up to him. I think they would have confided in Wharton, asked his advice, perhaps pleaded with him to help them cover up what they'd done.'

'It would explain why he began that spiral into depression and heavy drinking.'

'What? Do you think Mad Maurice had a guilty conscience?'

'Or he was afraid it would all come out. I bet he had nightmares about one of the people responsible making a mistake and letting something slip. They might have trusted Maurice. But did Maurice trust them?'

'So it's possible Maurice Wharton knew what had happened? Did he help Naylor and Gullick to conceal their crime?'

'Let's ask him.'

But Maurice Wharton was in no condition to answer questions. They found his wife and two children in the day room at the hospice, waiting in that tense, hushed atmosphere that fell in a hospital ward when the worst was expected.

'Can't you leave him alone?' said Nancy. 'What's the point of hara.s.sing the poor man now?'

'I'm sorry.'

'Oh, well. You can sit down for a minute, I suppose. Maurice was happy to talk to you the other day. Somebody different from the same old faces. He quite appreciated your visit.'