But here came giant Tsiolkovsky, the most distinctive crater on the whole damn far side of the Moon. Once, NASA had talked of putting an Apollo down, here in Tsiolkovsky, in the middle of the far side, with some kind of superannuated military relay satellite in orbit above it to keep the hapless astronauts in touch with home. Looking down now, he could see how dangerous that would have been, how treacherous Tsiolkovsky was.

“Forty seconds,” Geena said.

“Rog.”

“Press the switch over there. To your right.”

It was mounted on his back frame; he had to reach to get it. “What’s that?”

“The movie camera for the landing. IMAX. Twenty seconds. Engine armed. Pressed to proceed.” She grabbed the handrail. “Two, one.”

Ignition.

Henry could feel the thrust of the engine, silent and invisible as it was; it was like some mysterious gravity field, pulling him down to the surface of the Shoemaker.

The engine, he noted absently, had started up by itself.

“Hey,” he said. “Who’s flying this thing?”

“Autoland,” Geena said tightly.

The engine roared to full thrust, and the Shoemaker platform shook with a soundless, high-frequency vibration. His feet came to rest hard against the Shoemaker’s deck, and after five days in microgravity he welcomed the feel of acceleration.

“We’re burning, Arkady,” Geena said.

“I can see the glow in the engine bell. Godspeed, my friends.”

“Yeah. You too…”

…The ground lurched under Blue Ishiguro.

He’d been up here for hours. He had, he realized, been dozing.

He heard the growl of cracking rock, and he was thrown onto his back. Suddenly there was smoke everywhere, and the air was burning hot. He could see the clouds venting from new fissures, the white of superheated steam, the blue of sulphuric acid and fluorine. The stink was foul, like, he thought darkly, a high-school chemistry lab.

He straightened himself up, and surveyed the new situation.

Fissures had appeared on the flanks of the Campsie Fells. Lava fountains there, curtains of red flame following the lines of the fissures, rock droplets hurled metres into the air. As he watched, the fissures were spreading and merging.

A main vent, a broad crater, opened up in the hillside, facing Strathblane. More lava fountains, and now a major surge of sticky, viscous lava poured out. The heather on the hillside singed and burned in brief flashes. The cooling lava was already building up levees, and the molten material gushed down channels between the levees, heading towards the abandoned town.

Another, broader vent opened, and vomited lava.

Blue could smell sulphur and methane. Near the edge of the flow, loud cracks marked the explosion of methane gas. The fume clouds above the vents glowed orange against the blackening sky.

Blue?

“Sixt, I think it is starting. It was very sudden.”

He checked his cameras and instruments were stable, and that his data was indeed reaching orbit.