John had never seen so many hooded crows circling around the farm as he did that wet November morning. His father always used to say that whenever you saw more than seven hooded crows gathered together, they had come to gloat over a human tragedy.

It was tragedy weather, too. Curtains of rain had been trailing across the Nagle Mountains since well before dawn, and the north-west field was so heavy that it had taken him more than three hours to plow it. He was turning the tractor around by the top corner, close to the copse called Iollan's Wood, when he saw Gabriel frantically waving from the gate.

John waved back. Jesus, what did the idiot want now? If you gave Gabriel a job to do, you might just as well do it yourself, because he was always asking what to do next, and was it screws or nails you wanted, and what sort of wood were you after having this made from? John kept on steadily plowing, with big lumps of sticky mud pattering off the wheels, but Gabriel came struggling up the field toward him, still waving, with crows irritably flapping all around him. He was obviously shouting, too, although John couldn't hear him.

As Gabriel came puffing up to him in his raggedy old brown tweeds and gumboots, John switched off the tractor's engine and took off his ear-protectors.

"What's wrong now, Gabe? Did you forget which end of the shovel you're supposed to be digging with?"

"There's bones, John! Bones! So many fecking bones you can't even count them!"

John wiped the rain off his face with the back of his hand. "Bones? Where? What kind of bones?"

"Under the floor, John! People's bones! Come and see for yourself! The whole place looks like a fecking graveyard!"

John climbed down from the tractor and ankle-deep into the mud. Close up, Gabriel smelled strongly of stale beer, but John was quite aware that he drank while he worked, even though he went to considerable pains to conceal his cans of Murphy's under a heap of sacking at the back of the barn.

"We was digging the foundations close to the house when the boy says there's something in the ground here, and he digs away with his fingers and out comes this human skull with its eyes full of dirt. Then we were after digging some more and there was four more skulls and bones like you never seen the like of, leg-bones and arm-bones and finger-bones and rib-bones."

John strode long-legged down toward the gate. He was tall and dark, with thick black hair and almost Spanish good looks. He had only been back in Ireland for just over a year, and he was still finding it difficult to cope with running a farm. One sunny May morning he had been just about to close the door of his apartment on Jones Street in San Francisco when the telephone had rung, and it had been his mother, telling him that his father had suffered a massive stroke. And then, two days later, that his father was dead.

He hadn't intended to come back to Ireland, let alone take over the farm. But his mother had simply assumed that he would, him being the eldest boy, and all his uncles and aunts and cousins had greeted him as if he were head of the Meagher family now. He had flown back to San Francisco to sell his dot.com alternative medicine business and say goodbye to his friends, and here he was, walking through the gate of Meagher's Farm in a steady drizzle, with a beery-breathed Gabriel following close behind him.

"I'd say it was a mass murder," Gabriel panted.

"Well, we'll see."

The farmhouse was a wide green-painted building with a gray slate roof, with six or seven leafless elms standing at its south-eastern side like an embarrassed crowd of naked bathers. A sharply-sloping driveway led down to the road to Ballyhooly, to the north, and Cork City, eleven miles to the south. John crossed the muddy tarmac courtyard and went around to the north side of the house, where Gabriel and a boy called Finbar had already knocked down a rotten old feed store and were now excavating the foundations for a modernized boiler-house.

They had cleared an area twelve feet by twenty. The earth was black and raw and had the sour, distinctive smell of peat. Finbar was standing on the far side of the excavation, mournfully holding a shovel. He was a thin, pasty-faced lad with a closely-cropped head, protruding ears, and a soggy gray jumper.

On the ground in front of him, like a scene from Pol Pot's Cambodia, lay four human skulls. Nearer to the damp, cement-rendered wall of the farmhouse, there was a hole which was crowded with muddy human bones.

John hunkered down and stared at the skulls as if he were expecting them to explain themselves.

"God Almighty. These must have been here for a pretty long time. There isn't a scrap of flesh left on any of them."

"An unmarked grave, I'd say," put in Gabriel. "A bunch of fellows who got on the wrong side of the IRA."

"Scared the shite out of me," said Finbar, wiping his nose on his sleeve. "I was digging away and all of a sudden there was this skull grinning up at me like my old uncle Billy."

John picked up a long iron spike and prodded amongst the bones. He saw a jawbone, and part of a ribcage, and another skull. That made at least five bodies. There was only one thing to do, and that was to call the Garda.

"You don't think your dad knew about this?" asked Gabriel, as John walked back to the house.

"What do you mean? Of course he didn't know."

"Well, he was a great republican, your dad."

John stopped and stared at him. "What are you trying to say?"

"I'm not trying to say nothing, but if certain people wanted a place to hide certain remains that they didn't want nobody to find, your dad might have possibly obliged them, if you see what I mean."

"Oh, come on, Gabriel. My dad wouldn't have allowed bodies to be buried on his property."

"I wouldn't be too sure, John. There was certain stuff buried here once, under the cowshed, for a while."

"You mean guns?"

"I'm just saying that it might be better for all concerned if we forgot what we found here. They're dead and buried already, these fellows, why disturb them? Your dad's dead and buried, too, you don't want people raking over his reputation now, do you?"

John said, "Gabe, these are human beings, for Christ's sake. If we just cover them up, there are going to be five families who will never know where their sons or their husbands went. Can you imagine anything worse than that?"

"Well, I suppose you're right. But it still strikes me as stirring up trouble when there's no particular call to."

John went into the house. It was gloomy inside, and it always smelled of damp at this time of year. He took off his boots and washed his hands in the small cloakroom at the side of the hall. Then he went into the large quarry-tiled kitchen where his mother was baking. She seemed so small these days, with her white hair and her stooped back and her eyes as pale as milk. She was sieving out flour for tea brack.

"Did you finish the plowing, John?" she asked him.

"Not quite. I have to use the telephone."

He hesitated. She looked up and frowned at him. "Is everything all right?"

"Of course, mam. I have to make a phone call, that's all."

"You were going to ask me something." Oh, she was cute, his mother.

"Ask you something? No. Don't worry about it." If his father really had allowed the IRA to bury bodies on his land, he very much doubted that he would have confided in his mother. What you don't know can't knock on your door in the middle of the night.

He went into the living-room with its tapestry- covered furniture and its big red-brick fireplace, where three huge logs were crackling and Lucifer the black Labrador was stretched out on the rug with his legs indecently wide apart. He picked up the old-fashioned black telephone and dialed 112.

"Hallo? I want the Garda. I need to speak to somebody in charge. Yes. Well, this is John Meagher up at Meagher's Farm in Knocknadeenly. We've dug up some bodies."

It was raining even harder by the time Katie Maguire arrived at Meagher's Farm in her muddy silver Mondeo. She could see that Detective Inspector Liam Fennessy was already there, as well as two other detectives and three or four uniformed gardaí who were struggling against the gusty wind to erect bright blue plastic screens.

She climbed out of the car and walked across the farmyard with her raincoat collar turned up. Liam was standing by the open grave with his hands in the pockets of his long brown herringbone overcoat, undeterred by the rain, smoking a cigarette. Detective Garda Patrick O'Sullivan was hunkered down in his windcheater, frowning at the bones with a studious expression on his face, while Detective Sergeant Jimmy O'Rourke was standing under the shelter of the farmhouse roof, talking to John Meagher.

"Afternoon, superintendent," said Liam. He was thin and hollow-cheeked, with fair, greased-back hair and circular wire-rimmed spectacles, which were spotted with rain. He looked more like a young James Joyce than a Garda inspector. "Seems as if we've got a few bones to pick, doesn't it?"

"God almighty." She had never seen anything like this in her entire career. "How long before the team from the technical bureau get here?"

"Half-an-hour I'd say. And the venerable Dr Owen Reidy is coming down first thing tomorrow morning. Reidy the Ripper. He'd have your duodenum for a fancy necktie before you even breathed your last gasp."

Katie gave him the faintest of smiles. "Did you talk to Superintendent O'Connell in Naas?"

Jerry O'Connell was in charge of Operation Trace, which had spent the last nine years looking for eight young women who had disappeared without trace in the eastern counties of Ireland.

Liam said, "I put a message in, yes."

Katie walked slowly around the excavation, trying to make sense of all the bones that were lying there, jumbled up like pick-a-sticks as if somebody had tossed them up into the air and let them scatter at random. She could make out at least three pelvises, and two breastbones, and innumerable vertebrae.

She was used to dead bodies – three or four bluey-green floaters were fished out of the River Lee every week, and then there were the blackened and bloated druggies they regularly found in Lower Shandon Street, and the maroon-faced winos crouched in shop doorways in Maylor Street, their hearts stopped by Paddy's whiskey and hypothermia.

But this was different. This was wholesale butchery. She could almost smell the dread of what had happened here, along with the peaty reek of the rain-soaked soil.

Sergeant O'Rourke came up to her. He was a short, sandy-haired man with a rough-hewn block of a head, like an unfinished sculpture. "What do you think, Jimmy?" she asked him.

"I never saw nothing like it, ma'am, except in a picture on Father Francis' wall, at St Michael's, which had heaven at the top and hell at the bottom, you know, and this is what hell looked like. All skeletons, all in a heap."

Katie said, "This is John Meagher, is it?"

"That's right. John – this is Detective Superintendent Kathleen Maguire. She's in charge of this investigation."

John held out his hand. "Oh, I see. I'm sorry, I didn't realize that –"

"That's all right, John," said Katie. "An Garda Síochána is an equal-opportunity employer, and occasionally they bend over backwards to be very equal."

"It looks so far like there could be six skeletons, or even seven," said Sergeant O'Rourke. "Kevin's counted thirteen ankle-bones so far."

"Do you have any idea at all how these remains might have come to be buried here?" Katie asked John.

John shook his head. "None at all. Absolutely none. I've been running the farm for fourteen months now so nobody could have buried them here after I took over."

"What about before you took over?"

"Meagher's Farm has been in my family since 1935. I can't see my father burying any bodies here. Why would he? Nor my grandfather, either."

Katie nodded. "Does anybody else have access to your property here? Like tenant farmers, anybody like that? Or holidaymakers? Or Travelers?"

"There's nobody here but me and Gabriel and the Ryan brothers, Denis and Bryan. They do the general laboring, and Maureen O'Donovan helps me to run the creamery."

"I'll be wanting to talk to them, too."

"Sure, absolutely. But this is a total mystery, so far as I'm concerned. I'm no expert, but it looks me as if these people have been dead for a heck of a long time."

Katie said nothing, but stood looking at the bones with her hand pressed over her mouth.

John waited until Katie had walked around to the other side of the excavation before he said to Sergeant O'Rourke, "Kind of intense, isn't she?"

"Oh, not usually. But she's very humorless when it comes to homicide, Superintendent Maguire. Doesn't see the funny side of it, if you know what I mean."

John watched her as she circled around the bones. A very striking woman, he thought, not more than 5ft 5ins, just turned 40 maybe, with cropped coppery hair and sage-green eyes and sharply-chiseled cheekbones. She had that Irish-elfin look of being related to the fairy folk, ten generations removed. The sort of woman you find yourself looking at a second time, and then again. But then she glanced up and caught him looking at her and he found himself immediately turning away, as if he had something to be guilty about. God knows how she would make him feel if he actually knew how these skeletons had come to be buried here.

Eventually she came back over. The raindrops were sparkling in her hair. "You haven't heard any local stories about anybody going missing? Not necessarily recent stories. Something that might give us a rough idea when these people died."

"I don't have too much time for local gossip, I'm afraid. I go down to Ballyvolane once in a while and have a couple of drinks at the Fox and Hounds. But I'm still a foreigner, as far as the locals are concerned. Not surprising, really. I still can't understand the Cork accent and up until I came here I thought that hurling was something you did after drinking too much Guinness."

"All right, John," said Katie. "You won't be going anywhere, will you? Once we've had the chance to clear this site properly; and the State Pathologist has examined the remains, there'll be quite a few more questions that are going to need answering."

"Listen, whatever I can do."

Katie went over to her car and picked up her mobile phone. "Paul? It's me. I'm up at Knocknadeenly. Yes, somebody's found some remains. Yes, I know. Listen, it doesn't look as if I'm going to be home until late. There's a Marks & Spencer chicken pie in the freezer. You put it in a pre-heated oven at gas mark 8. Yes. Well, you know how to peel a potato, don't you? All right, go to the pub if you like, it's up to you, but eat something decent. I'll call you later."

A white Garda van was coming up the driveway. The technical bureau. Katie walked back to the excavation and waited for them to kit up in their Tyvek suits and their rubber boots. She looked down at the heap of bones and wondered who on earth they had belonged to. Normally, when she attended a death scene, it was immediately obvious who had done what to whom, and why. Bloody carving-knives in the kitchen sink. Babies, gray-faced from suffocation. Girls lying face-down and muddy-thighed in a ditch somewhere, strangled with their own scarves.

But this was something very different, and until she knew how long these people had been lying here it was futile for her to try and guess who might have killed them, or why. All that was immediately apparent was that none of the skulls had a bullet-hole in the back. That would have been very strong evidence that they were the victims of a political execution, or maybe a revenge killing by one of the local gangs.

Although she was going to inform Operation Trace about these skeletons as a matter of protocol, she didn't think that they were connected with Superintendent O'Connell's investigation. The girls he was looking for had disappeared one by one over nearly a decade – the last one in July, 1998 – and Katie's immediate impression was that these bodies had been buried all at once.

Liam came up to her and offered her an extra-strong mint. "What do you think? Could have been Meagher's father who did it, possibly?"

"We won't know that until we find out who all these people were, and when they were killed, and why."

"You're not looking for a motive? Look around you – a Godforsaken place like this. Struggling from dawn to dusk to scrape a half-decent living and nobody to take out your economic and sexual frustrations on, except the livestock, or the occasional passing cyclist, looking for somewhere to spend the night. Remember that bed-and-breakfast business, down in Crosshaven? Three of them, stuffed in an airing-cupboard?"