Beer lines snaked up towards the bar, and a bewildering assortment of equipment lay around, some of it on shelves or left on empty kegs, or stored in the corner of the cellar. He saw a wooden mallet, stainless-steel buckets, disposable paper towels, a scrubbing brush, a pressure hosepipe, filter funnels and papers, a dip stick, beer taps and a gas bottle spanner.

A tiny space off the cellar had been turned into an office. Well, more of a storage room really, with a few dusty filing cabinets lined up against the wall, a desk covered in box files, and a pile of old magazines – The Publican, Morning Advertiser.

On a shelf, Cooper found a stack of old sepia and black-and-white photographs in their frames, which must once have hung on the walls upstairs. He picked up a particularly old photo in a gilt frame, and wiped the dust off the glass. It was a group shot, taken some time around the start of the twentieth century, he guessed. A formally arranged bunch of people was pictured outside the front entrance of a pub. A large man with enormous whiskers posed importantly in the middle of the group, with men in leather aprons and women in white smocks spread out on either side and behind him, some of them standing, others sitting awkwardly on wooden chairs brought outside from the bar.

The pub was recognisably the Light House, its windows almost unchanged to the present day, the shape of its chimneys visible along the top of the print. But the lettering painted over the door didn’t say The Light House. The pub had gone by a different name a century ago. Cooper squinted a bit more closely, trying to make out the lettering. Surely it was …? Yes, he was sure. The pub had once been called the Burning Woman.

He put the photo down, and it slid off the pile with a scrape of glass. His automatic sense of disturbance at the name was probably a twenty-first-century response. No one would have thought anything of it back then. There were plenty of rural pubs whose names reflected gruesome episodes from history, or some lurid folk tale. The people of these parts seemed to have had particularly vivid and bloodthirsty imaginations.

He couldn’t see the swinging wooden sign because of the angle the photograph had been taken from, but he guessed there would be a suitably graphic image to accompany the name. Someone would know the legend of the burning woman. Stories like that survived by word of mouth long after the signs had been taken down and the names sanitised.

‘I can’t help feeling the moulds are sending their spores directly towards me, even as I speak,’ said Villiers.

‘How did they get deliveries?’ asked Cooper ‘Can you see?’

‘Over here.’

The double cellar doors to the outside were at the top of a narrow set of stone steps, with equally narrow ramps on either side. The hatches themselves were bolted on the inside. The bolts and hinges were old and starting to rust, reminding Cooper of the iron plate over the abandoned mine shaft.

He couldn’t see even a crack of daylight round the edges of the doors. He tried to figure out where they emerged. Why hadn’t he noticed them from the outside? The only possible answer was that they too were covered by something. He remembered the pile of old furniture stacked against the back wall. Heavy tables with metal bases, wrought-iron chairs, a heap of torn parasols on steel posts. They had been chucked on a mound like so much rubbish. They must be lying right on top of the cellar doors. Maybe it had been for additional security. Or perhaps no one expected beer deliveries to be made at this pub for the foreseeable future.

‘What was through there?’ asked Villiers.

‘A desk, a few filing cabinets. Loads of old paperwork just mouldering away. I suppose it’s been left for the new owners, if anyone buys the pub at the auction.’

‘What sort of paperwork?’

‘Accounts, I suppose. Orders, deliveries, records of paying guests, VAT returns. Whatever. That would be part of the business history, wouldn’t it? If you took the place on, you’d want to get an idea of how many bookings there were for the rooms. The time of year, where they came from and all that.’

‘Yes, of course. But we’re not thinking of buying the pub, are we? I mean – are we?’

‘No. But it seems to me that the information we want might be down here anyway. We need to get scenes of crime here.’

Cooper inhaled deeply. He was trying to detect the presence of other smells in the cellar that shouldn’t be there. No stink of petrol, thank goodness. So at least Maurice Wharton hadn’t kept a motorbike down here. But his brain was running along another track. He was thinking of the temperature control. That cool twelve degrees Celsius.

‘Carol, what is the temperature inside your fridge?’

Villiers looked startled. ‘A fridge should be about three degrees Celsius. Anything higher and you have the risk of bacteria. Anything lower and food starts to freeze.’

‘I didn’t know that,’ said Cooper.

‘Don’t worry. Food probably doesn’t stay long enough in your fridge for it to matter.’

Cooper nodded thoughtfully. Twelve degrees was too warm, then. Too high a temperature to preserve anything for very long. There would definitely be a smell by now.

‘What are you thinking, Ben?’ asked Villiers, watching the expression on his face.

‘Oh, nothing important,’ he said. ‘I was just wondering about the deterioration in the quality of the beer down here.’

‘Ben, that wasn’t what you were thinking at all,’ said Villiers.

He liked the way Carol understood him. She never seemed to read the wrong messages as Diane Fry so often used to do when they worked together.

‘No,’ said Cooper. ‘You’re right.’

In fact, the memory that had been eluding him had just come back exactly as he’d hoped, in a moment when he wasn’t even trying to remember it. He’d recalled a look from Betty Wheatcroft, the slightly dotty old woman, the former teacher who’d been so disappointed at his lack of knowledge, the way teachers in his childhood always had been.

‘No, actually,’ he said, ‘I wasn’t thinking about that at all. I was thinking about the ninth circle of hell.’

Diane Fry took Henry Pearson into the little office she’d been given. She felt a bit embarrassed by it, because it was so clearly makeshift. None of the furniture even pretended to match, and the walls showed unfaded patches where the previous occupant had taken down his charts and year planners.

She promised herself she would have a better office one day. And it wouldn’t be too long now, either.

But Pearson didn’t seem to notice, or care, what sort of room he was in. He sat in the only available chair, declined tea or coffee, but accepted a glass of water.

He’d brought his briefcase with him, no doubt containing those files Fry had seen him carrying so importantly on the TV news. When he placed it on the desk, her heart sank. She hoped he wasn’t about to whip out a file and start trying to win her over to his case. His obsessive earnestness reminded her of UFO nuts, conspiracy theorists and other cranks she’d encountered. Mostly harmless, but not the sort of person you’d want to get cornered by at a party.

Instead, he produced his leather-bound writing pad, opened it and placed a pen next to it before giving her his attention.

‘First of all,’ she said, ‘I realise that some of my questions will have been asked before.’

‘Many times, I’m sure,’ said Pearson. ‘The same questions have been asked over and over until I know them by heart. It was a surprise to me at first, the way the police work. But I’m accustomed to it now. Hardened would perhaps be a better word.’

‘I understand.’

His grey hair was smoothed neatly back, and his eyes regarded her sharply. She remembered how, when he’d arrived in Edendale earlier in the week, he’d studied each officer he met, as if hoping to see something in them that he hadn’t yet found.