After brunch, I put on the clothes. I got dressed in the bathroom; Sam was still there, and I wanted to do this in private. The clothes felt like something more: fine chain-mail armor handmade to fit me, or robes laid out ready for some fiercely secret ceremony. They made my palms tingle when I touched them.

Plain white cotton underwear with the Penney’s tags still on; faded jeans, worn soft and fraying at the hems; brown socks, brown ankle boots; a long-sleeved white T-shirt; a pale-blue suede jacket, scuffed but clean. The collar of it smelled of lilies of the valley and something else, a warm note almost too faint to catch: Lexie’s skin. In one of the pockets there was a Dunne’s Stores receipt from a few weeks back, for chicken fillets, shampoo, butter and a bottle of ginger ale.

When I was dressed I checked myself out, in the full-length mirror on the back of the door. For a second I didn’t know what I was seeing. Then, ridiculously, all I wanted was to laugh. It was the irony of it: I had spent months dressing up as Executive Barbie, and now that I was being someone else, I finally got to go to work dressed a lot like me. “You look nice,” Sam said, with a faint smile, when I came out. “Comfortable.”

My stuff was packed and waiting by the door, as if I were off on some voyage; I felt like I should be checking my passport and tickets. Frank had bought me a nice new traveling case, the hard kind, with discreet reinforcement and a solid combination lock; it would take a safecracker to get in there. Inside were Lexie’s things-wallet, keys, phone, all dead ringers for the real things; the stuff from the housemates; a plastic tub of vitamin C tablets with a pharmacist’s label that said AMOXICILLIN TABS TAKE ONE THREE TIMES DAILY, to go somewhere prominent. My gear was in a separate compartment: latex gloves, my mobile, spare battery packs for the mike, a supply of artistically stained bandages to go in the bathroom bin every morning and evening, my notebook, my ID and my new gun-Frank had got me a.38 snub-nose that felt good in my hand and was a lot easier to hide than my regulation Smith amp; Wesson. There was also-seriously-a girdle, the industrial-strength elastic kind that’s supposed to give you a smooth silhouette in your Little Black Dress. It’s a lot of undercovers’ version of a holster. It’s not comfortable-after an hour or two you feel like there’s a gun-shaped dent in your liver-but it does a good job of hiding the outline. Just the thought of Frank going into the Marks amp; Sparks lingerie department and picking it out made this whole thing worthwhile.

“You look like shite,” he said, examining me approvingly, when he arrived at the door of my flat. He was carrying a double armful of Bond-looking black electronics, cables and speakers and God knows what: the setup for the wire. “The eye bags are to die for.”

“She’s had three hours’ sleep a night,” Sam said tightly, behind me. “Same as yourself and myself. And we’re not exactly looking the best either.”

“Hey, I’m not giving her hassle,” Frank told him, heading past us and dumping the armful on the coffee table. “I’m delighted with her. She looks like she’s been in intensive care for ten days. Hi, babe.”

The mike was tiny, the size of a shirt button. It clipped onto the front of my bra, between my breasts: “Lucky our girl didn’t go in for low-cut tops,” Frank said, glancing at his watch. “Go lean over in front of the mirror, check the view.” The battery pack went where the knife wound should have been, surgical-taped to my side under a thick pad of white gauze, just an inch or two below the scar Dealer Boy had left on Lexie Madison the First. The sound quality, once Frank had done small complicated things to the equipment, was crystal clear: “Only the best for you, babe. Transmission radius is seven miles, depending on conditions. We’ve got receivers set up at Rathowen station and at the Murder squad, so you’ll be covered at home and in Trinity. The only time you’ll go out of coverage is on the drive to and from town, and I don’t anticipate anyone shoving you out of a moving car. You won’t have visual surveillance, so any visuals that we should know about, tell us. If the shit hits the fan and you need a subtle way to yell for help, say ‘My throat hurts’ and you’ll have big-time backup on the scene inside a few minutes-don’t go getting a sore throat for real, or if you do, don’t complain about it. You need to check in with me as often as possible, ideally every day.”

“And with me,” Sam said, not turning around from the sink. Frank, squatting on the floor and squinting at some dial on his receiver, didn’t even bother to throw me a mocking look.

Sam finished the washing up and started drying things too thoroughly. I sorted the Lexie material into some kind of order-that high-wire final-exam feeling, taking your hands off your notes at last, If I don’t know it now-stacked it in bundles and packed it into plastic bags, to leave in Frank’s car. “And that,” Frank said, unplugging the speakers with a flourish, “should do it. Are we good to go?”

“Ready when you are,” I said, picking up the plastic bags. Frank swept up his equipment one-armed, grabbed my case and headed for the door.

“I’ll take that,” Sam said brusquely. “You’ve enough to carry,” and he took the case from Frank’s hand and headed down the stairs, the wheels hitting each step with a hard dull thump.

On the landing Frank turned and looked back over his shoulder, waiting for me. My hand was on the door handle when for a split second out of nowhere I was terrified, blue-blazing terrified, fear dropping straight through me like a jagged black stone falling fast. I’d felt this before, in the limbo instants before I moved out of my aunt’s house, lost my virginity, took my oath as a police officer: those instants when the irrevocable thing you wanted so much suddenly turns real and solid, inches away and speeding at you, a bottomless river rising and no way back once it’s crossed. I had to catch myself back from crying out like a little kid drowning in terror, I don’t want to do this any more.

All you can do with that moment is bite down and wait for it to be over. The thought of what Frank would have to say, if I actually pulled out now, helped a lot. I took one more look around my flat-lights off, water heater off, bins emptied, window locked; the room was already closing in on itself, silence seeping into the spaces where we had been, drifting up like dust in the corners. Then I shut the door.

The drive down to Glenskehy took almost an hour, even with no traffic and Frank driving, and it should have been excruciating. Sam slumped miserably in the back seat, next to the gadgetry; Frank helped the atmosphere by turning up 98FM nice and loud and bopping along, whistling and nodding his head and beating time on the steering wheel. I barely even noticed either of them. It was a gorgeous afternoon, sunny and crisp, I was out of my flat for the first time in a full week, and I had the window rolled all the way down and wind streaking through my hair. That hard black stone of fear had dissolved the second Frank started the car, turned into something sweet and lemon-colored and wildly intoxicating.

“Right,” Frank said, when we hit Glenskehy, “let’s see how well you’ve learned your geography. Give me directions.”

“Straight on through the village, fourth lane to your right, way too narrow, no wonder Daniel and Justin’s cars look like they’ve been drag racing, give me good old dirty Dublin any day,” I told him, doing his accent. “ Home, James.” I was on a giddy one. The jacket had been freaking me out all afternoon-it was that lily-of-the-valley smell, right up close, I kept whipping round to see who had come up beside me-and the fact that I was being given the heebiejeebies by a jacket, like something out of Dr. Seuss, was making me want to giggle. Even passing the turnoff to the cottage, where I had met Frank and Sam that first day, didn’t sober me up.