"When in doubt, shop," she told us, slamming the car door.

William sat tight-lipped, looking in his rear-view mirror at the argument continuing further up the slip. "Bastards," he said. "People are so fucking inconsiderate."

"Shoot the lot of them," I said, thinking about getting out and having a cigarette (no smoking on the champagne-hued leather of the Merc).

"Yeah," William said, hands kneading the steering wheel. "People might be a bit more polite if everybody carried guns."

I looked at him.

It was all sorted out after some confusion and a lot of ill-feeling; the BMW people moved their boat forward so cars and trailers could get past it to the road. We picked Yvonne up at the top of the slip by the RNLI shed where they sold stuff to help pay for the lifeboat.

She didn't seem to have bought much; she tossed me a box of matches as she got into the car. "Here," she said.

I studied the matchbox. "Wo. Hey, you sure about this?"

I looked back as we powered away up the hill through the trees, heading for Edinburgh. There was another commotion going on down on the slip; the BMW people were gesticulating wildly and pointing at the tyres on one side of the trailer holding the big ski boat, which appeared to be listing slightly in that direction now. It looked like it was all getting rather heated again down there; then the leaves got in the way and we couldn't see any more. I was sure I'd seen a punch thrown.

I turned back to find Yvonne's grinning face looking past me in the same direction. She looked suddenly innocent and sat back in her seat, humming. I remembered the time Andy and I had let down all the wheels of his dad's car, folding matches in half and sticking them into the tyre valves. I opened the box of matches Yvonne had given me, but you couldn't have told whether there were a couple of them missing or not.

"Looks like they had some sort of problem with their trailer there," I said.

"Good," William said.

"Probably a puncture," Yvonne sighed. She glanced at William. "We do have lockable tyre valves on this thing, don't we?"

William in the woods, outskirts of Edinburgh, almost within sight of the estate where his and Yvonne's new house is, toting a paint gun on another of these stupid but grudgingly-sometimes-fun-in-a-terribly-boyish-sort-of-way paint-ball games (his computer-company boys and girls versus the crack troops of the Caledonian news room). My gun jammed and William recognised me and came forward laughing and firing shot after shot at me while I waved and tried to duck and these yellow paint balls went splat, splat, thunking into my hired camouflage trousers and combat jacket and smacking into my visored helmet while I waved at him and tried to get the damn gun to work and he just walked forward slowly shooting me; bastard had his own paint gun and he'd probably had it souped up; knowing William, that was almost inevitable. Splat! Splat! Splat! He was getting closer and I was thinking, Christ does he know about me and Yvonne? Has he guessed, has somebody told him, is that what all this is about?

It was pretty fucking annoying even if it wasn't; I really wanted to get the bastard because we'd been having this stupid argument before we'd started about how greed really was good and how William had been so disappointed at how poorly the argument was put across by the Gekko character in Wall Street.

"But it is good," William protested, waving his gun around. "That's how we measure fitness to survive these days." We were being shown round the paint-ball site, having flagpoles and log barricades and that sort of stuff pointed out to us. "It's natural," William insisted. "It's evolution; when we still lived in caves we used to go out and hunt and whoever brought back the mammoth or whatever ate the best meat and got to fuck the women, and all that was good for the human race. Now it's got a bit more abstract and we use money instead of animals but the principle's the same."

"But it wasn't just individuals who hunted animals; that's exactly the point," I told him. "It was all about cooperation; people worked together and got results and shared the spoils."

"I agree," William agreed. "Cooperation is great. If people didn't cooperate you couldn't lead them so easily."

"But —»

"And you'll always need leaders."

"But greed and selfishness —»

"— have produced everything you see around you," William said, waving the paint-ball gun around again.

"Exactly!" I exclaimed, throwing my arms out wide. "Capitalism!"

"Yes! Exactly!" William echoed, also gesturing with his hands. And we stood there, me with a great big frown on my face, quite mystified that William couldn't see what I was getting at… and William smiling but looking equally puzzled that I appeared to be incapable of understanding what he meant.

I shook my head, exasperated, and brandished my paint-ball gun. "Let's fight," I said.

William grinned. "I rest my case."

So I really wanted to nail the bastard — preferably with the cooperation of my team-mates just to prove the point — but the fucking technology let me down and the gun jammed and he had me pinned, firing shot after shot at me, and finally I gave up trying to un-jam the gun and made to throw it at him though I could hardly see because there was yellow paint all over my visor, but he ducked and tripped and sat down on a trunk, holding his stomach, and the bastard was laughing his socks off because I looked like a giant dripping banana, only I'd just realised the gun wasn't jammed after all, the safety catch was on. I must have knocked it or something and I'd a couple of shots left and I ought to have shot the swine but I couldn't, not while he was sitting there killing himself laughing.

"Bastard!" I yelled at him.

He twirled his paint gun around one gloved ringer. "Evolution!" he shouted. "You learn a lot when you live with a liquidator!" He started laughing again.

Later at the buffet lunch in the marquee he barged to the front of the queue saying, "Oh, I don't believe in queuing!" and when somebody behind him objected, convinced her with a sort of apologetic bashfulness that actually he has diabetes, you see, and so needs to eat right now. I cringed, blushed, and looked away.

Still thinking; thinking about all the times I've seen people I know do something for revenge, or do anything vindictive or sneaky or smart or even threaten to. Hell, everybody I know's done something like that at some time or another but that doesn't make them a murderer; I think McDunn's crazy but I can't tell him that because, if he's wrong about that and I'm wrong about it being something to do with those guys who died in the Lake District a few years ago, then there's only one suspect left and that's me. The trouble is my theory's looking shakier all the time because McDunn's convinced me it really was all just a smoke-screen: there is no Ares project, never was any Ares project, and Smout in his prison in Baghdad isn't connected to the guys that died; it was just somebody coming up with a clever conspiracy theory, just a way of getting me to go to remote places and wait for phone calls and deprive me of an alibi while gorilla man did something horrible to somebody else somewhere else. Of course McDunn points out that I could still be the murderer; this could all be a story I've made up. I could have recorded the mysterious Mr Archer's phone calls and had them directed to the office while I was there. They found most of the equipment to do just that in my flat when they searched it: an answer-machine, my PC and its modem; another lead or two and it would have been easy to set it up if you knew what you were doing, or just used trial and error and were patient.