"Why?" I demanded. I found this both intriguing and mildly disconcerting; I am not religious, and as far as I knew Cassie wasn't either.

"Oh, because we do. Every single society in the world, ever, has had some form of belief system. But now…How many people do you know who're Christian-not just going to church, but actually Christian, like trying to do things the way Jesus would've? And it's not like people can have faith in political ideologies. Our government doesn't even have an ideology, as far as anyone can tell-"

"'A Little Something for the Boys,'" I said, over my shoulder. "That's an ideology, of sorts."

"Hey," said Sam mildly.

"Sorry," I said. "I didn't mean anyone specific." He nodded.

"Neither did I, Sam," said Cassie. "I just meant there isn't one overall philosophy. So people have to make their own faith."

I had found whiskey, Coke, ice and three glasses; I juggled them all back to the coffee table in one go. "What, you mean Religion Lite? All those New Age yuppies having tantric sex and feng shui-ing their SUVs?"

"Them, too, but I was thinking of the people who make a religion out of something completely different. Like money-actually, that's the nearest thing the government has to an ideology, and I'm not talking about bribes, Sam. Nowadays it's not just unfortunate if you have a low-paid job, have you noticed? It's actually irresponsible: you're not a good member of society, you're being very very naughty not to have a big house and a fancy car."

"But if anyone asks for a raise," I said, whapping the ice tray, "they're being very very naughty to threaten their employer's profit margin, after everything he's done for the economy."

"Exactly. If you're not rich, you're a lesser being who shouldn't have the gall to expect a living wage from the decent people who are."

"Ah, now," Sam said. "I don't think things are that bad."

There was a small, polite silence. I collected stray ice cubes from the coffee table. Sam by nature has a Pollyanna streak, but he also has the kind of family that owns houses in Ballsbridge. His views on socioeconomic matters, though sweet, could hardly be considered objective.

"The other big religion these days," Cassie said, "is bodies. All those patronizing ads and news reports about smoking and drinking and fitness-"

I was pouring, looking at Sam for a signal to stop; he lifted a hand, smiled at me as I passed him the glass. "Those always make me want to see how many cigarettes I can fit in my mouth at once," I said. Cassie had stretched her legs across the futon; I moved them out of the way so I could sit down, put them back across my lap and started making her drink, lots of ice and lots of Coke.

"Me, too. But those reports and stuff aren't just saying things are unhealthy-they're saying they're morally wrong. Like you're somehow a better person, spiritually, if you have the right body-fat percentage and exercise for an hour a day-and there's that awful condescending set of ads where smoking isn't just a stupid thing to do, it's literally the devil. People need a moral code, to help them make decisions. All this bio-yogurt virtue and financial self-righteousness are just filling the gap in the market. But the problem is that it's all backwards. It's not that you do the right thing and hope it pays off; the morally right thing is by definition the thing that gives the biggest payoff."

"Drink your drink," I said. She was lit up and gesturing, leaning forward, her glass forgotten in her hand. "What does this have to do with batty Mark again?"

Cassie made a face at me and took a sip of her drink. "Look: Mark believes in archaeology-in his heritage. That's his faith. It's not some abstract set of principles, and it's not about his body or his bank account; it's a concrete part of his whole life, every day, whether it pays off or not. He lives in it. That's not batty, that's healthy, and there's something seriously wrong with a society where people think it's weird."

"The guy poured a fucking libation to some Bronze Age god," I said. "I don't think there's anything particularly wrong with me for considering that a little odd. Back me up here, Sam."

"Me?" Sam had settled back into the sofa, listening to the conversation and reaching out to finger the tumble of shells and rocks on the windowsill. "Ah, I'd say he's just young. He should get himself a wife and a few kids. That'd settle him."

Cassie and I looked at each other and started to laugh. "What?" Sam demanded.

"Nothing," I said, "honestly."

"I'd love to get you and Mark together over a couple of pints," Cassie said.

"I'd soon sort him out," Sam said serenely, sending Cassie and me into a fresh fit of giggles. I leaned back into the futon and took a sip of my drink. I was enjoying this conversation. It was a good evening, a happy evening; soft rain was pittering at the windows and Billie Holiday was playing in the background and I was glad, after all, that Cassie had invited Sam. I was starting to like him a lot more actively. Everyone, I decided, should have a Sam around.

"Do you seriously think we can eliminate Mark?" I asked Cassie.

She sipped her drink, balanced the glass on her stomach. "Actually, I honestly do," she said. "Regardless of the battiness question. Like I said, I get this very strong sense that whoever did this was in two minds about it. I can't imagine Mark being in two minds about anything-at least, not anything important."

"Lucky Mark," Sam said, smiling at her across the coffee table.

"So," Sam asked, later, "how did you and Cassie meet?" He leaned back on the sofa and reached for his glass.

"What?" I said. It was sort of a weird question, out of the blue like that, and to be honest I had half-forgotten he was there. Cassie buys good booze, silky Connemara whiskey that tastes like turf smoke, and we were all a little tipsy. The conversation was starting, comfortably, to ebb. Sam had been stretching to read the titles of the battered paperbacks on the bookshelf; I had been lying back on the futon, thinking about nothing more taxing than the music. Cassie was in the bathroom. "Oh. When she joined the squad. Her bike broke down one evening and I gave her a lift."

"Ah. Right," Sam said. He looked slightly flustered, which wasn't like him. "That's what I thought at first, sure: that you hadn't met before. But then it seemed like you'd known each other for ages, so I just wondered were you old friends or…you know."

"We get that a lot," I said. People tended to assume we were cousins or had grown up next door to each other or something along those lines, and it always filled me with a private, unreasonable happiness. "We just hit it off well, I suppose."

Sam nodded. "You and Cassie," he said, and cleared his throat.

"What'd I do?" Cassie demanded suspiciously, shoving my feet out of the way and sliding back into her seat.

"God only knows," I said.

"I was only asking Rob whether the two of ye knew each other before you joined Murder," Sam explained. "From college or something."

"I didn't go to college," I said. I had a feeling that I knew what he had been going to ask me. Most people do ask, sooner or later, but I hadn't had Sam down as the inquisitive type, and I wondered why, exactly, he wanted to know.

"Seriously?" Sam said, startled and trying not to show it. This is what I mean about the accent. "I thought Trinity, maybe, and you had classes together, or…"

"Didn't know him from Adam," Cassie said blandly, which after a frozen instant sent her and me into helpless, snorting, juvenile giggles. Sam shook his head, smiling.

"One as mad as the other," he said, and got up to empty the ashtray.