There was a clattering noise behind them. Tollemache whirled, drawing his gun. ‘Fucking woodies.’

‘What? You mean builders. We call them builders.’

‘I know you do, and I don’t care. Annoying little bastards. Not even much use for target practice.’ But he raised his gun anyhow.

So this was how the builders had been excluded from their forest. ‘Leave them alone,’ Yuri said, suddenly angry. ‘They’ve more right to be here than you have, Peacekeeper.’

Tollemache grunted, but moved on.

‘So,’ Delga called back. ‘The Ad Astra’s long gone, and you’re still here, Tollemache.’

‘Not all of it.’

‘What?’

‘Not all the Ad Astra left. You’ll see. They split the ship, dropped one of the hulls here, at the substellar.’

And Yuri remembered sighting the ship in his telescope, when it was still in orbit, with just a single hull.

‘Turned it into a long-term hab. They weren’t going to let you shitters run around killing yourselves without some monitoring, were they? Although all we ever do is keep score. It’s not so bad. We got a five-hundred-year nuke power plant, hot water, downloads from Earth, everything. They asked for volunteers to man it.’

Delga laughed. ‘You actually volunteered, you dumb schmuck.’

Tollemache was not a man to hide his anger. ‘You keep that up and I’ll stitch you a new tattoo before we get to the base.’

‘But you volunteered,’ she persisted.

‘Five years. That was the deal. They were building another ship, going to send it out. They’d cycle us back to Earth after five years. They were offering a hell of a bonus.’

‘But they never came back,’ Delga said.

‘Incredible,’ Yuri mused. ‘They told us it would be a century before another call. What they told us was more true than what they told you.’

Delga laughed again. ‘What’s it like in there after twenty years, Tollemache? Worn out the pause button on your porn machine yet?’

‘Fuck off, lizard lady – hey! What the hell?’

There was a blur of motion to their left, a clattering like chopsticks.

‘It was the builders,’ the ColU said calmly. ‘They were following us, at a distance. And now—’

‘They just took off,’ Liu said.

‘Where to?’

‘How should I know?’

‘They seemed keen to find something, deep in this forest,’ the ColU said. ‘A forest from which they have been excluded for some time, remember.’

Yuri eyed Liu.

‘Let’s go and see,’ Liu said.

‘Hell, yes. Come on, before we lose them!’

They both ducked off the trail and into the deeper forest.

‘Hey!’ Tollemache yelled. ‘Get back here, you little shits!’

Yuri heard Delga cackling.

Ahead, Yuri could just see a builder, skittering and whirling. He lunged on, but quickly lost sight of his prey. ‘Liu – which way now?’

‘Right, I think. I just saw – yeah! There. Come on!’

They plunged into the forest, crashing through ever denser foliage, moving as fast as they could, trying not to lose sight of the fleeing builders, outpacing the ColU. But Yuri quickly tired in the smothering heat. There was no sense of direction in this dense, clinging forest, no shadows cast from the clouded-over sky – and the overhead sun would have been no use for wayfinding anyhow. Yuri was soon turned around, with no idea which way they had come, where they had got to.

Then they came to a clearing.

They stood inside the last rank of trees, breathing hard. This open space, maybe twenty paces across, was a rough circle. No trees grew here, but there was a thick bed of stems over a patch of swampy ground.

And the builders were here, the nine who had travelled in with them from the lake to the north. They whirled and clattered and skimmed across the muddy ground, dragging away stems as they went. Every so often two or three would encounter each other, and they would share their peculiar dance-like communications.

‘We need the ColU,’ Liu said, breathless. ‘I wonder what the hell they’re talking about.’

‘I don’t know. But they’re clearing those stems pretty quickly.’

It seemed only minutes before a patch of ground, a rough square maybe ten metres across, had been cleared. Now some of the builders worked their way through the exposed mud, whirring around like propeller blades. Others were hastily digging out a kind of trench, leading away from the central area, through which water was soon trickling.

‘Look at that,’ Liu said. ‘They’re draining this bit of swamp.’

‘Yeah. And digging up the mud. See how hard they’re working. Like they’re desperate to do this. This is what they’ve been excluded from, I guess. Come on, we’ll help. Let’s get filthy.’ Yuri got down on his hands and knees in the clinging mud, and began to haul at the heavy stuff, picking up handfuls and hurling it away.

Liu grunted, then got down warily. ‘OK. But when my heart gives out, go get Nurse Tollemache . . .’

The two men made little impact on the mud layer compared to the remarkably efficient spinning of the builders. Nevertheless Yuri soon got down a metre or more in the patch he was digging.

And then he found a hard surface, under the mud. Shocked, he pulled back.

He dug in again, clearing a space. That deep surface was hard, flat – and cold, certainly colder than the mud that overlay it, colder than the air in the forest clearing. Growing excited now, he hauled at the mud in great armfuls, until he had exposed a stretch of some kind of floor, perfectly flat, grey, hard to the touch.

Liu was staring. ‘I found the same. What the hell is it? Some kind of metal?’

‘I don’t know.’

‘An artefact? Human, or . . .’

Yuri just shrugged. He was beyond questions.

‘How come Tollemache doesn’t know about this? If they’d found it you’d think they’d have it dug out by now.’ He laughed. ‘Or stuck it on a plinth in the UN Plaza.’

‘Tollemache doesn’t know because he never looked. They must have chased away the builders rather than watch what they were up to.’

He thought he saw a seam now, a fine line in the surface, so fine it was almost invisible. He traced it with his thumb. He dug out the mud, working backwards on his knees, exposing more seam. It seemed to be curving inward, gradually. He dug and dug, following the seam.

Until Liu tapped him on the shoulder. ‘Time to take a step back, buddy.’

Yuri stood, covered in mud, panting, sweating. He’d forgotten how hot he was.

And he saw that while he’d dug his clumsy trench the builders had cleared the rest of the area. They had exposed a metallic floor, still mud-streaked but gleaming in the grey light of the clouds. There were shapes cut into the upper surface, like three-pointed starbursts a metre or so across – clusters of three at a time, all the way across the floor.

‘There’s your seam,’ Liu said, pointing.

It was a perfect circle maybe three metres across, cut into the grey floor. It seemed obvious what this was. Set in the ground of this alien world, known only to the builders, it was –

‘A hatch,’ Yuri said. ‘We found a hatch.’

CHAPTER 55

When Yuri, Liu and Tollemache finally got to the Peacekeepers’ encampment after their diversion to the builders’ hatch, they found the Ad Astra hull lying on its side in the substellar forest. After more than two decades mature trees crowded around the hull, obscuring it, so that coming upon it was like discovering the relic of some lost civilisation. Huge cargo-bay doors were raised at the rear end of the hull, exposing garages, workshops, stores; tarpaulins hung over the doors to keep out the rain, lashed down against the wind.

By the time Yuri and the others arrived, the driver had backed his rover into a bay in the belly of the hull. The ColU was parked up too. Yuri saw its camera eyes fixed on him with a longing to know what they had found. ‘Later, buddy,’ he murmured.