“Definitely no idiot. None of them are, but especially not him. You’ll need to watch your step around that one.”

I ignored that. “Justin Mannering,” Frank said, moving on. Justin had got himself wound up in a snarl of white Christmas lights and was giving them a helpless look. He was tall, too, but in a narrow, prematurely professorial way: short mousy hair already starting to recede, little rimless glasses, long gentle face. “From Belfast. Doing his PhD on sacred and profane love in Renaissance literature, whatever profane love may be; sounds to me like it would cost a couple of quid a minute. Mother died when he was seven, father remarried, two half brothers, Justin doesn’t go home much. But Daddy-Daddy’s a lawyer-still pays his fees and sends money every month. Nice for some, eh?”

“They can’t help it if their parents have money,” I said absently.

“They could get a bloody job, couldn’t they? Lexie gave tutorials, marked papers, invigilated exams-she worked in a café, till they moved out to Glenskehy and the commute got too complicated. Didn’t you work in college?”

“I waited tables in a pub, and it sucked. No way would I have done it if I’d had any choice. Getting your arse pinched by drunk accountants doesn’t necessarily make you a better person.”

Frank shrugged. “I don’t like people who get everything for free. Speaking of whom: Raphael Hyland, goes by Rafe. Sarky little fucker. Daddy’s a merchant banker, originally from Dublin, moved to London in the seventies; Mummy’s a socialite. They divorced when he was six, dumped him straight into boarding school, moved him every couple of years when Daddy got another raise and could afford to trade up. Rafe lives off his trust fund. Doing his PhD on the malcontent in Jacobean drama.”

Rafe was stretched out on a sofa with a glass of wine and a Santa hat, being purely ornamental and doing it well. He was ridiculously beautiful, in that way that makes a lot of guys feel a panicky urge to come out with snide comments in their deepest voices. He was the same general height and build as Justin, but his face was all bones and dangerous curves, and he was gold all over: heavy dark-blond hair, that skin that always looks faintly tanned, long iced-tea eyes hooded like a hawk’s. He was like a mask from some Egyptian prince’s tomb.

“Wow,” I said. “All of a sudden this gig looks more tempting.”

“If you’re good, I won’t tell your fella you said that. The guy’s probably a bender anyway,” Frank said, with crashing predictability. “Last but not least: Abigail Stone. Goes by Abby.”

Abby wasn’t pretty, exactly-small, with shoulder-length brown hair and a snub nose-but there was something about her face: the quirk of her eyebrows and the twist of her mouth gave her a quizzical air that made you want to look twice. She was sitting in front of a turf fire, threading popcorn for garlands, but she was giving the cameraperson-Lexie, presumably-a wry look, and the blur of her free hand made me think she had just whipped a piece of popcorn at the camera.

“She’s a very different story,” Frank said. “From Dublin, father was never on the scene, mother dumped her in foster care when she was ten. Abby aced her Leaving Cert, got into Trinity, worked her arse off and came out with a first. PhD on social class in Victorian literature. Used to pay her way by cleaning offices and tutoring schoolkids in English; now that she doesn’t have rent to pay-Daniel doesn’t charge them-she picks up a few bob giving tutorials in college and helping her professor with research. You’ll get on.”

Even caught off guard like that, the four of them made you want to keep looking. Partly it was the sheer luminous perfection of it all-I could practically smell gingerbread baking and hear carolers in the background, they were about one robin redbreast away from a greeting card. Partly it was the way they dressed, austere, almost Puritan: the guys’ shirts dazzling white, knife creases in their trousers, Abby’s long woolen skirt tucked demurely round her knees, not a logo or a slogan in sight. Back when I was a student, all our clothes always looked as if they had been washed once too often in a dodgy laundrette with off-brand detergent, which they had. These guys were so pristine it was almost eerie. Separately they might have looked subdued, even boring, in the middle of Dublin’s orgy of designer-label self-expression, but together: they had a cool, challenging quadruple gaze that made them not just eccentric but alien, something from another century, remote and formidable. Like most detectives-and Frank knew this, of course he did-I’ve never been able to look away from anything that I can’t figure out.

“They’re quite a bunch,” I said.

“They’re a weird bunch, is what they are, according to the rest of the English department. The four of them met when they started college, almost seven years ago now. Been inseparable ever since; no time for anyone else. They’re not particularly popular in the department-the other students think they’re up themselves, amazingly enough. But somehow our girl got in with them, almost as soon as she started at Trinity. Other people tried to make friends with her, but she wasn’t interested. She’d set her sights on this lot.”

I could see why, and I warmed towards her, just a little. Whatever else about this girl, she hadn’t had cheap taste. “What have you told them?”

Frank grinned. “Once she got to the cottage and passed out, the shock and the cold sent her into a hypothermic coma. That slowed down her heartbeat-so anyone who found her could easily have thought she was dead, right?-stopped the blood loss and prevented organ damage. Cooper says it’s ‘clinically ludicrous, but quite possibly plausible to those with no medical knowledge,’ which is fine by me. So far no one seems to have a problem with it.”

He lit up and blew smoke rings at the ceiling. “She’s still unconscious and it’s touch and go, but she might well pull through. You never know.”

I wasn’t about to rise to that. “They’ll want to see her,” I said.

“They already asked. Unfortunately, due to security concerns, we are unable to disclose her location at this time.”

He was enjoying this. “How’d they take it?” I asked.

Frank thought about that for a while, head leaned back on the sofa, smoking slowly. “Shaken up,” he said at last, “naturally enough. But there’s no way of knowing whether they’re all four shaky because she got stabbed, or whether one of them’s shaky because she might come round and tell us what happened. They’re very helpful, answer all our questions, no reluctance, nothing like that; it’s only afterwards that you realize they haven’t actually told you very much at all. They’re an odd bunch, Cass; hard to read. I’d love to see what you make of them.”

I swept the photos into a pile and passed them back to Frank. “OK,” I said. “Why did you need to come over and show me these, again?”

He shrugged, all wide innocent blue eyes. “To see if you recognized any of them. That could give a whole different angle-”

“I don’t. Come clean, Frankie. What do you want?”

Frank sighed. He tapped the photos methodically on the table, aligning the edges, and tucked them back into his jacket pocket.

“I want to know,” he said quietly, “if I’m wasting my time here. I need to know if you’re one hundred percent sure that what you want is to go back into work on Monday morning, to DV, and forget this ever happened.”

All the laughter and façade had gone out of his voice, and I knew Frank well enough to know that this was when he was most dangerous. “I’m not sure I have the option of forgetting about it,” I said, carefully. “This thing’s thrown me for a loop. I don’t like it, and I don’t want to get involved.”

“You’re sure about that? Because I’ve been working my arse off these last two days, pumping everyone in sight for every detail of Lexie Madison’s life-”