Dave didn't say a word on the drive back. The sleet had stopped, and when we got out of the car in Quarry Fields, the air was fresh and crisp, and a star-flecked fissure had cleft the sky. The ground was snapping underfoot as we walked up the drive.

I checked my phone. Tommy had sent me a text message, all in capitals: WATCH OUT! LEO'S AFTER YOU! I figured having a high-ranking Garda detective as my guest was a reasonable precaution against anything Leo Halligan might do.

I brewed a pot of coffee and we sat at the kitchen table. Dave started by saying that Aidan Coyne, the Guard who'd been on duty at the mortuary, had worked with him at Seafield, that he was a good lad and that he wouldn't breathe a word to anyone about our visit. It was known in Bray station that Dave had served with Don Kennedy, and nobody was very happy about how Dave had been sidelined in the investigation. And there was always resentment when the National Bureau of Criminal Investigation started throwing their weight around with the local force, especially if Myles Geraghty had anything to do with it. Dave had told Aidan a version of the truth: that he wanted to say a few quiet prayers for a fallen comrade.

When the coffee was ready I poured two mugs. I had put the heat on, but Dave was shivering, and he asked if he could have some Jameson in his. That struck me as a good idea, so I had some in mine too. We drank for a while in silence. I knew he was waiting for me to spill all I knew. I was happy enough that we had made a deal. We just needed to check the small print before we took it any further.

"Dave, I'm not looking for a partner here. I want to be free to do things the way I would do them. And if that means withholding information, or taking a risk by following a hunch-"

"Or riding the arse off one of the chief suspects, or all of them; yeah, I know how you work, Ed."

Dave guffawed in what struck me as a rather forced manner, and I pretended to, hoping my laughter would spare my blushes, or his; I'd never heard him make that kind of remark before, and he didn't seem relaxed about having made it. I wondered briefly if Dave had been the one tailing me tonight. Not that Miranda Hart was a suspect. I didn't even know what the case was yet-another reason I didn't want anyone looking over my shoulder.

"Don't worry-you won't have to answer to me. I'll feed you whatever you need, and you can go your own way."

"If I didn't trust you, Dave, I'd think I was being set up. You're not setting me up, are you?"

"Ed, this fucker Geraghty is a bad cop. He's a rotten cop. I don't want to tell you what I know about him, but let's just say anything that can publicly embarrass him, any way I can trip the cunt up, anything to help push him out the door and I'll be happy."

"I don't get it, Dave. What's in it for you? I mean, say we get to the killer, or killers, before the Garda investigation does. We've still got to hand it over. I can't arrest murderers myself. And no one's going to give you credit for conducting some kind of maverick case. Quite the opposite."

"Well, let's say that's my lookout, and leave it at that," Dave said bluntly, in a tone that brooked no further discussion. He laid a spiral bound reporter's pad on the table and looked at me expectantly.

A cat or a fox set the security light on in the back. I stared out at the two bare apple trees in the center of the garden, male and female, their branches nearly touching and never quite. I wondered briefly about Dave and Carmel, then as quickly put them from my mind: they had been rock solid since school, one of those partnerships where you could never see the join-however much Dave tried to portray the marriage as if it were something from the Dark Ages. Carmel was forever asking me around to the house, but the truth was, the warmth and energy and happiness they had built there always left me feeling desolate and bereft. No, those trees were a gloss first off on my parents' ill-fated match, and latterly on the sorry chronicle of my own romantic history.

I didn't tell Dave that Vincent Tyrrell had hired me. But I went through most everything else: the likelihood that Don Kennedy was the PI Miranda Hart had hired at the insurance company's behest to find Patrick Hutton; the fact that Hutton and Leo Halligan had been apprentices together at Tyrrellscourt after their joint stint at St. Jude's reform school (Dave lifted his head from the pad for that one, his eyes wide, especially when he heard that Leo was fresh out of jail); the death of the racehorse By Your Leave; the consequent rift between Hutton and F. X. Tyrrell and its significance in Hutton's disappearance; Hutton's emotional declaration that he wouldn't play the Judas for anyone; the bizarre and formidable force that was Jackie Tyrrell and her insinuation, barely countered by Miranda Hart, that Halligan and Hutton had a sexual relationship; the omega and crucifix tattoos on Patrick Hutton's forearm.

Dave stared at his pad in silence when I had finished. He looked up and shook his head, smiling at first. Then the smile faded from his broad face, and his mouth set, and his eyes hardened and flickered like jewels, and I had a reminder of what it felt like to sit across from him in an interrogation room. It didn't feel very comfortable.

"I went to the scene myself, Ed. I knew Geraghty wouldn't like that, so I didn't tell him. But I went there anyway, and I did what I guess you probably did: I gave the body a quick once-over and then I called it in to Bray station, along with the tip-off about Vinnie Butler. Bad enough a private cop risking the contamination of a crime scene, but a real cop? Why would he do that?"

"I don't know, Dave. Why did he do that?"

"Because he knew that the private cop wasn't really to be trusted. He knew that if the private cop found something really juicy, he'd keep it to himself. And he wanted to find out just what it was the private cop was holding back."

"And did he?"

"There had been a piece of paper-a note, I'd say-in the victim's left trouser pocket. There were still shreds of paper adhering to the pocket fibers, which suggests that it had been freshly removed; there were mild ink stains on the pocket fabric, from which, as with the paper shreds, we might infer that the note had been through the wash with the trousers."

"Do you do this for a living?"

"What was written on the note?"

"The mobile phone number for a bookie who had a pitch at Gowran Park racecourse today."

"Do you know which bookie that was?"

"Not yet. But I still have the number."

"Anything else you want to tell me?"

"I didn't want to tell you that."

"If I told Geraghty you'd interfered with the body-worse, you'd stolen evidence-what do you think he'd do?"

"I have an idea what he'd do with me. What would he do with you?"

"He'd probably blame me for knowing you."

"There you are. Not to mention what he'd do if he was told you had given the scene a surreptitious one-two first."

And there we were. He had me, but I had him. MAD: Mutually Assured Destruction, they used to call it when it came to nuclear missiles. Safe as houses, unless one of us actually went mad. Dave wasn't looking completely sane to me. He topped his coffee up with Jameson, laughing gently and nodding in private agreement with himself. Then he clapped his hands and almost winked.

"So what did you make of this Miranda Hart then Ed? Is she a looker, is she?"

It suddenly occurred to me that Dave might have formed as idealized a picture of my single life as I possibly had of his married one. I threw him a look I was more used to getting from him. The look said: Cop yourself on, you tool. It landed right between his eyes and spread crimson across his face.