But right now he felt fine. Better than fine, in fact. He felt alert, confident. When he looked up above, he could see a line of white light, the sunlit upper face of the rille. Actually, he felt a little high.

He had no doubts, suddenly, that he would live through this; in a couple of minutes he would be with Geena, and then back to the shelter, and Earth, and in a few years it would be no more than a sea story he could share with Jane…

He was flat against the rock face, being dragged upward, almost passively.

Now he was approaching daylight. He was being hauled up the shallow upper slope of the rille, like a swordfish being landed on some Greek island beach.

He seemed to be lying on his back. The sun, a ball of white light, flooded his helmet. He turned his head towards it and let all that pure light pour into his open eyes. It was really quite beautiful. And there were colours, like the kaleidoscopic sparkle of a granite thin slice in his petrological microscope, all around him, the colours of the Moon.

But now there was somebody before him, a snowman figure loping around him as if in a dream. He — or she — reached down and closed something over his face, and the world turned to gold.

He closed his eyes.

Gold, grey, black.

Henry’s backpack was just a ruin. Crushed and overheated. Even his emergency oxygen supply, from the purge tanks, seemed to have failed. He was clearly suffering hypoxia. A few more minutes of this and he would suffer permanent brain damage.

Geena dug hoses out of her backpack. She coupled her own emergency air supply to Henry’s. That would be enough for an hour or so. Then she hooked up more hoses so Henry could share her supply of cooling water; he’d broil before they got back to the shelter otherwise.

She was tempted to peer into his helmet, to see if he was breathing, if he was responding. But it wouldn’t do any good. What could she do, take off his gloves to see if his fingernails were blue?

She pulled him up. He half-stood, inert, like a statue, so stiff was his suit. She managed to get his arm over her shoulder, her arm around his waist. Under lunar gravity he only weighed a couple of stone, but he was awkward, a stiff, massive shape. As she hauled him back towards the Rover, his feet dragged in the regolith.

It was going to be a race back to the shelter, to get Henry inside before that emergency pack expired. At least driving back would be easier. They only had to follow their own tracks back, to be sure of their destination.

But if anything else went wrong — if a fault developed with her own backpack, or the thirty-year-old Rover — it was quite possible neither of them would live through this.