O'Kelly lost patience. He hates being baffled, and the charged, crisscrossing tensions in the room must have been setting his teeth on edge just as badly as the case itself. "That's great, Maddox. Thanks for that. So what the hell do you suggest? Come on; let's hear you come up with something useful, instead of sitting there shooting down everyone else's ideas."

Cassie stopped drawing and carefully balanced her pen across one finger. "OK," she said. "Psychopaths get their kicks by having power over other people-manipulating them, inflicting pain. I think we should try playing to that. Give her all the power she can eat, and see if she gets carried away."

"What are you talking about?"

"Last night," Cassie said slowly, "Rosalind accused me of sleeping with Detective Ryan."

Sam's head turned sharply towards me. I kept my eyes on O'Kelly. "Oh, I hadn't forgotten, believe me," he said heavily. "And it bloody well better not be true. You two are both in deep enough shite already."

"No," Cassie said, a trifle wearily, "it's not true. She was just trying to distract me and hoping she would hit a nerve. She didn't, but she doesn't know that for sure; I could just have been covering very well."

"So?" O'Kelly demanded.

"So," Cassie said, "I could go talk to her, admit that Detective Ryan and I have a longstanding affair, and beg her not to turn us in-maybe tell her we suspect she was involved in Katy's death and offer to tell her how much we know in exchange for her silence, something like that."

O'Kelly snorted. "And what, you think she'll just spill her guts?"

She shrugged. "I don't see why not. Yeah, most people hate to admit they've done something terrible, even if they won't get in trouble for it; but that's because they feel bad about it, and because they don't want other people to think less of them. To this girl, other people aren't real, any more than characters in a video game, and right and wrong are just words. It's not like she feels any guilt or remorse or anything about having Damien kill Katy. In fact, I'm willing to bet she's over the moon with herself. This is her greatest achievement yet, and she hasn't been able to brag to anyone about it. If she's sure she has the upper hand, and she's sure I'm not wearing a wire-and would I wear a wire to admit to sleeping with my partner?-I think she'll jump at the chance. The thought of telling a detective exactly what she did, knowing there's not a thing I can do about it, knowing it must be killing me… It'll be one of the most delicious buzzes of her life. She won't be able to resist."

"She can say whatever she bloody well likes," O'Kelly said. "Without a caution, none of it will be admissible."

"So I'll caution her."

"And you think she'll keep talking? I thought you said the girl's not crazy."

"I don't know," Cassie said. She sounded, just for a second, exhausted and openly pissed off, and it made her seem very young, like a teenager unable to conceal her frustration with the idiotic adult world. "I just think it's our best shot. If we go for a formal interview, she'll be on her guard, she'll sit there and deny everything, and we'll have blown our shot: she'll go home knowing there's no way we can pin anything on her. This way, at least there's a chance she'll figure I can't prove anything and take the risk of talking."

O'Kelly was grating a thumbnail, monotonously and infuriatingly, over the fake-wood grain of the table; he was obviously thinking about it. "If we do it, you wear a wire. I'm not risking this on your word against hers."

"I wouldn't have it any other way," Cassie said coolly.

"Cassie," Sam said very gently, leaning forward across the table, "are you sure you're able for this?" I felt a sudden flare of anger, no less painful for being utterly unjustifiable: it should have been my place, not his, to ask the question.

"I'll be fine," Cassie told him, with a little one-sided smile. "Hey, I did undercover for months and never got spotted once. Oscar material, me."

I didn't think this was what Sam had been asking. Just telling me about that guy in college had left her practically catatonic, and I could see that same distant, dilated look starting in her eyes again, hear the too-detached note in her voice. I thought of that first evening, across the stalled Vespa: how I had wanted to sweep her under my coat, protect her even from the rain.

"I could do it," I said, too loudly. "Rosalind likes me."

"No," O'Kelly snapped, "you couldn't."

Cassie rubbed her eyes with finger and thumb, pinched the bridge of her nose as if she had a headache starting. "No offense," she said flatly, "but Rosalind Devlin doesn't like you any more than she likes me. She's not capable of that emotion. She finds you useful. She knows she has you wrapped around her little finger-or had you; whichever-and she's sure you're the one cop who, if it comes to it, will believe she's been wrongfully accused and fight her corner. Believe me, there's not a chance in hell she's going to throw that away by confessing to you. Me, I'm no use to her anyway; she has nothing to lose by talking to me. She knows I dislike her, but that just means she'll get an extra thrill out of having me at her mercy."

"All right," O'Kelly said, shoving his stuff into a pile and pushing back his chair. "Let's do it. Maddox, I hope to God you know what you're talking about. First thing tomorrow morning, we'll get you wired up and you can go have a girly chat with Rosalind Devlin. I'll make sure they give you something voice-activated, so you can't forget to hit Record."

"No," Cassie said. "No recorder. I want a transmitter, feeding to a backup van less than two hundred yards away."

"To interview an eighteen-year-old kid?" O'Kelly said contemptuously. "Have some balls, Maddox. This isn't Al-Qaeda here."

"To go one-on-one with a psychopath who just murdered her little sister."

"She's got no history of violence herself," I said. I didn't intend it to sound bitchy, but Cassie's eyes passed briefly over me, with no expression in them at all, as if I didn't exist.

"Transmitter and backup," she repeated.

I didn't go home that night until three in the morning, when I could be sure that Heather would be asleep. Instead I drove out to Bray, to the seafront, and sat there in the car. It had finally stopped raining and the night was dense with mist; the tide was in, I could hear the slap and rush of the water, but I caught only the odd glimpse of the waves between the swirls of erasing gray. The gay little pavilion drifted in and out of existence like something from Brigadoon. Somewhere a foghorn sounded one melancholy note over and over, and people walking home along the seafront materialized gradually out of nothingness, silhouettes floating in midair like dark messengers.

I thought about a lot of things, that night. I thought of Cassie in Lyons, just a girl in an apron, serving coffee at sunny outdoor tables and bantering in French with the customers. I thought of my parents getting ready to go out dancing: the careful lines my father's comb left in his Brylcreemed hair, the rousing scent of my mother's perfume and her flower-patterned dress whisking out the door. I thought of Jonathan and Cathal and Shane, long-limbed and rash and laughing fiercely over their lighter games; of Sam at a big wooden table amid seven noisy brothers and sisters, and of Damien in some hushed college library filling out an application for a job at Knocknaree. I thought of Mark's reckless eyes-The only things I believe in are out on that there dig-and then of revolutionaries waving ragged, gallant banners, of refugees swimming swift nighttime currents; of all those who hold life so light, or the stakes so dear, that they can walk steady and open-eyed to meet the thing that will take or transform their lives and whose high cold criteria are far beyond our understanding. I tried, for a long time, to remember bringing my mother wildflowers.