We palmed off the McLoughlin case (the one we had been working till we got this call: two God-awful little rich boys who had kicked another to death when he jumped the queue for a late-night taxi) on Quigley and his brand-new partner McCann, and went to find ourselves an incident room. The incident rooms are too small and always in demand, but we had no trouble getting one: children take priority. By that time Sam had got in-he had been held up in traffic as well; he has a house somewhere in Westmeath, a couple of hours out of town, which is as near as our generation can afford to buy-so we grabbed him and briefed him, with full harmonies and the official hair-clip story, while we set up the incident room.

"Ah, Jesus," he said, when we finished. "Tell me it wasn't the parents."

Every detective has a certain kind of case that he or she finds almost unbearable, against which the usual shield of practiced professional detachment turns brittle and untrustworthy. Cassie, though nobody else knows this, has nightmares when she works rape-murders; I, displaying a singular lack of originality, have serious trouble with murdered children; and, apparently, family killings gave Sam the heebie-jeebies. This case could turn out to be perfect for all three of us.

"We haven't a clue," Cassie said, through a mouthful of marker cap; she was scribbling a timeline of Katy's last day across the whiteboard. "We might have a better idea once Cooper comes back with the results from the post, but right now it's wide open."

"We don't need you to look into the parents, though," I said. I was Blu-Tacking crime-scene photos to the other side of the board. "We want you to take the motorway angle-trace the phone calls to Devlin, find out who owns the land around the site, who has a serious stake in the motorway staying put."

"Is this because of my uncle?" Sam asked. He has a tendency to directness that I've always found slightly startling, in a detective.

Cassie spat out the marker cap and turned to face him. "Yeah," she said. "Is that going to be a problem?"

We all knew what she was asking. Irish politics are tribal, incestuous, tangled and furtive, incomprehensible even to many of the people involved. To an outside eye there is basically no difference between the two main parties, which occupy identical self-satisfied positions on the far right of the spectrum, but many people are still passionate about one or the other because of which side their great-grandfathers fought on during the Civil War, or because Daddy does business with the local candidate and says he's a lovely fella. Corruption is taken for granted, even grudgingly admired: the guerrilla cunning of the colonized is still ingrained into us, and tax evasion and shady deals are seen as forms of the same spirit of rebellion that hid horses and seed potatoes from the British.

And a huge amount of the corruption centers on that primal, clichéd Irish passion, land. Property developers and politicians are traditionally bosom buddies, and just about every major land deal involves brown envelopes and inexplicable rezoning and complicated transactions through offshore accounts. It would be a minor miracle if there weren't at least a few favors to friends woven into the Knocknaree motorway, somewhere. If there were, it was unlikely that Redmond O'Neill didn't know about them, and equally unlikely that he would want them to come out.

"No," Sam said, promptly and firmly. "No problem." Cassie and I must have looked dubious, because he glanced back and forth between us and laughed. "Listen, lads, I've known him all my life. I lived with them for a couple of years when I first came up to Dublin. I'd know if he was into anything dodgy. He's straight as a die, my uncle. He'll help us out any way he can."

"Perfect," Cassie said, and went back to the timeline. "We're having dinner at my place. Come over around eight and we'll swap updates." She found a clean corner of whiteboard and drew Sam a little map of how to get there.

By the time we had the incident room organized, the floaters were starting to arrive. O'Kelly had got us about three dozen of them, and they were the cream of the crop: up-and-comers, alert and smooth-shaven and dressed for success, tipped to make good squads as soon as the openings arose. They pulled out chairs and notebooks, slapped backs and resurrected old in-jokes and chose their seats like kids on the first day of school. Cassie and Sam and I smiled and shook hands and thanked them for joining us. I recognized a couple of them-an uncommunicative dark guy from Mayo called Sweeney, and a well-fed Corkman with no neck, O'Connor or O'Gorman or something, who compensated for having to take orders from two non-Corkonians by making some incomprehensible but clearly triumphalistic comment about Gaelic football. A lot of the others looked familiar, but the names went straight out of my head the moment their hands slid away from mine, and the faces merged into one big, eager, intimidating blur.

I've always loved this moment in an investigation, the moment before the first briefing begins. It reminds me of the focused, private buzz before a curtain goes up: orchestra tuning, dancers backstage doing last-minute stretches, ears pricked for the signal to throw off their wraps and leg warmers and explode into action. I had never been in charge of an investigation anything like this size before, though, and this time the sense of anticipation just made me edgy. The incident room felt too full, all that primed and cocked energy, all those curious eyes on us. I remembered the way I used to look at Murder detectives, back when I was a floater praying to be borrowed for cases like this one: the awe, the bursting, almost unbearable aspiration. These guys-a lot of them were older than I was-seemed to me to have a different air about them, a cool, unconcealed assessment. I've never liked being the center of attention.

O'Kelly slammed the door behind him, slicing off the noise instantaneously. "Right, lads," he said, into the silence. "Welcome to Operation Vestal. What's a vestal when it's at home?"

Headquarters picks the names for operations. They range from the obvious through the cryptic to the downright weird. Apparently the image of the little dead girl on the ancient altar had piqued someone's cultural tendencies. "A sacrificial virgin," I said.

"A votary," said Cassie.

"Jesus fuck," said O'Kelly. "Are they trying to make everyone think this was some cult thing? What the fuck are they reading up there?"

Cassie gave them a rundown on the case, skipping lightly over the 1984 connection-just an off-chance, something she could check out in her spare time-and we handed out jobs: go door-to-door through the estate, set up a tip line and a roster for manning it, get a list of all the sex offenders living near Knocknaree, check with the British cops and with the ports and airports to see if anyone suspicious had come over to Ireland in the last few days, pull Katy's medical records, her school records, run full background checks on the Devlins. The floaters snapped smartly into action, and Sam and Cassie and I left them to it and went to see how Cooper was getting on.

We don't normally watch the autopsies. Someone who was at the crime scene has to go, to confirm that this is in fact the same body (it's happened, toe tags getting mixed up, the pathologist ringing a startled detective to report his finding of death from liver cancer), but mostly we palm this off on uniforms or techs and just go through the notes and photos with Cooper afterwards. By squad tradition you attend the post-mortem in your first murder case, and although supposedly the purpose is to impress you with the full solemnity of your new job, nobody is fooled: this is an initiation rite, as harshly judged as any primitive tribe's. I know an excellent detective who, after fifteen years on the squad, is still known as Secretariat because of the speed with which he left the morgue when the pathologist removed the victim's brain. I made it through mine (a teenage prostitute, thin arms layered with bruises and track marks) without flinching, but I was left with no desire to repeat the experience. I go only in those few cases-ironically, the most harrowing ones-that seem to demand this small, sacrificial act of devotion. I don't think anyone ever quite gets over that first time, really, the mind's violent revolt when the pathologist slices the scalp and the victim's face folds away from the skull, malleable and meaningless as a Halloween mask.