"Sometimes I think he'd like me to die," Anna said, "I have dreams about it."

We walked back and I built up the fire and mixed some cocoa, using powdered milk. Everything was dark now except for the flames, sparks going up in spirals, coals underneath pulsing red when the night breeze hit them. We sat on the groundsheets, David with his arm around Anna, Joe and I a foot apart.

"This reminds me of Girl Guides," Anna said in the cheerful voice I once thought was hers. She began to sing, the notes hesitant, quavering:

There'll be bluebirds over

The white cliffs of Dover

Tomorrow, when the world is free…

The words went out towards the shadows, smoke-thin, evaporating. Across the lake a barred owl was calling, quick and soft like a wing beating against the eardrum, cutting across the pattern of her voice, negating her. She glanced behind her: she felt it.

"Now everybody sing," she said, clapping her hands.

David said "Well, goodnight children," and he and Anna went into their tent. The tent lit up from inside for a moment, flashlight, then went out.

"Coming?" Joe said.

"In a minute." I wanted to give him time to go to sleep.

I sat in the dark, the stroking sound of the night lake surrounding me. In the distance the Americans' campfire glowed, a dull red cyclops eye: the enemy lines. I wished evil towards them: Let them suffer, I prayed, tip their canoe, burn them, rip them open. Owl: answer, no answer.

I crawled into the tent through the mosquito-netting; I groped for the flashlight but didn't switch it on, I didn't want to disturb him. I undressed by touch; he was obscure beside me, inert, comforting as a log. Perhaps that was the only time there could be anything like love, when he was asleep, demanding nothing. I passed my hand lightly over his shoulder as I would touch a tree or a stone.

But he wasn't sleeping; he moved, reached over for me.

"I'm sorry," I said, "I thought you were asleep."

"Okay," he said, "I give up, you win. We'll forget everything I said and do it like you want, back to the way it was before, right?"

It was too late, I couldn't. "No," I said. I had already moved out.

His hand tightened in anger on my arm; then he let go. "Sweet flaming balls of Christ," he said. His outline lifted in the darkness, I crouched down, he was going to hit me; but he turned over away from me, muffling himself in the sleeping bag.

My heart bumped, I held still, translating the noises on the other side of the canvas wall. Squeaks, shuffling in the dry leaves, grunting, nocturnal animals; no danger.

The tent roof was translucent, wet parchment, spotted on the outside with early dew. Bird voices twirled over my ears, intricate as skaters or running water, the air filling with liquid syllables.

In the middle of the night there was a roar, Joe having a nightmare. I touched him, it was safe, he was trapped in the straitjacket sleeping bag. He sat up, not yet awake. "This is the wrong room," he said.

"What was it?" I asked. "What were you dreaming?" I wanted to know, perhaps I could remember how. But he folded over and went back.

My hand was beside me; it had the cured hide smell of wood-smoke mingled with sweat and earth, fish lingering, smell of the past. At the cabin we would soak the clothes we'd been wearing, scrub the forest out of them, renew our coating of soap and lotion.

I dressed and went down to the lake and dipped my face into it. This water was not clear like the water in the main lake: it was brownish, complicated by more kinds of life crowded more closely together, and it was colder. The rock ledge dropped straight down, lake of the edge. I woke the others.

After I'd cleaned the fish I dipped them in flour and fried them and boiled coffee. The fish flesh was white, blue-veined; it tasted like underwater and reeds. They ate, not talking much; they hadn't slept well.

Anna's face in the daylight was dried and slightly shrivelled without its cream underfilm and pink highlights; her nose was sunburned and she had prune crinkles under her eyes. She kept turned away from David, but he didn't seem to notice, he didn't say anything, except when she knocked her foot against his cup and tipped some of his coffee out onto the ground. Then all he said was "Watch it Anna, you're getting sloppy."

"Do you want to fish any more this morning?" I said to David, but he shook his head: "Let's go take that rock painting."

I burned the fish bones, the spines fragile as petals; the innards I planted in the forest. They were not seeds, in the spring no minnows would sprout up. Deer skeleton we found on the island, shreds of flesh on it still, he said the wolves had killed it in the winter because it was old, that was natural. If we dived for them and used our teeth to catch them, fighting on their own grounds, that would be fair, but hooks were substitutes and air wasn't their place.

The two of them fiddled with the movie camera, adjusting and discussing it; then we could start.

According to the map the rock painting was in a bay near the Americans' camp. They didn't seem to be up yet, there was no smoke coming from their fireplace. I thought, maybe it worked and they're dead.

I looked for a dip in the shore, a line that would fit the mapline. It was there, site of the x, unmistakable: cliff with sheer face, the kind they would have chosen to paint on, no other flat rock in sight. He had been here and long before him the original ones, the first explorers, leaving behind them their sign, word, but not its meaning. I leaned forward, scanning the cliff surface; we let the canoes drift in sideways till they scraped the stone.

"Where is it?" David said; and to Joe, "You'll have to steady the canoe, there's no way we can shoot from land."

"It might be hard to see at first," I said, "Faded. It ought to be right here somewhere." But it wasn't: no man with antlers, nothing like red paint or even a stain, the rock surface extended under my hand, coarse-grained, lunar, broken only by a pink-white vein of quartz that ran across it, a diagonal marking the slow tilt of the land; nothing human.

Either I hadn't remembered the map properly or what he'd written on the map was wrong. I'd reasoned it out, unravelled the clues in his puzzle the way he taught us and they'd led nowhere. I felt as though he'd lied to me.

"Who told you about it?" David said, cross-examining.

"I just thought it was here," I said. "Someone mentioned it. Maybe it was another lake." For a moment I knew: of course, the lake had been flooded, it would be twenty feet under water. But that was the other lake, this one was part of a separate system, the watershed divided them. The map said he'd found them on the main lake too; according to the letter he'd been taking pictures of them. But when I'd searched the cabin there had been no camera. No drawings, no camera, I'd done it wrong, I would have to look again.

They were disappointed, they'd expected something picturesque or bizarre, something they could utilize. He hadn't followed the rules, he'd cheated, I wanted to confront him, demand an explanation: You said it would be here.

We turned back. The Americans were up, they were still alive; they were setting out in their canoe, the front one had his fishing rod trailing over the bow. Joe and I were ahead, we approached them at right angles.

"Hi," the front one said, to me, bleached grin. "Any luck?" That was their armour, bland ignorance, heads empty as weather balloons: with that they could defend themselves against anything. Straight power, they mainlined it; I imagined the surge of electricity, nerve juice, as they hit it, brought it down, flapping like a crippled plane. The innocents get slaughtered because they exist, I thought, there is nothing inside the happy killers to restrain them, no conscience or piety; for them the only things worthy of life were human, their own kind of human, framed in the proper clothes and gimmicks, laminated. It would have been different in those countries where an animal is the soul of an ancestor or the child of a god, at least they would have felt guilt.