Then I heard it: it was the same buzzing noise that I’d heard all my life, and I realised that, since I’d been outside, I’d been vaguely perturbed by its absence.

‘And the lights have stayed on,’ I noted. ‘That’s odd. Shouldn’t everything have been switched off, stopped?’

‘In this world, how can we tell what’s normal? Just as well, anyway! We hadn’t thought of that.’

The lights never did go out.

Neither of us wanted to enter the big room that housed the cage. But we forced ourselves to, before we did anything else, so as not to spoil the pleasure of exploring. The last traces of apprehension vanished when we saw that everything was exactly as we’d left it. We hoped to take the mattresses, because we’d slept on the ground, levelled with the shovel, joking that we’d lost the only comfort the prison had had to offer.

‘They’re too heavy,’ I protested. ‘I don’t see how we could carry them if we move on. We can take them up, but we can only use them if we decide to stay put.’

‘And that would be ridiculous. We must look for civilisation.’

‘What civilisation?’

Anthea looked at me.

‘What do you mean?’

I shrugged.

‘Just think about it. This planet belongs to them, so what would we find other than the people who held us captive? I have no wish to meet them.’

‘You think we’re on another planet.’

It wasn’t a question, but a statement. I wasn’t entirely convinced of what I was saying. I never found out for certain either.

Then we went into the room off to the right, the one that contained a table and a few chairs. Along the wall were six tall, narrow cupboards which Anthea told me were called lockers and were always found in workplaces for people to keep their things in. They were open. In each one, we found two pairs of boots, and I couldn’t remember if these were the ones I’d seen. Anthea took them out and placed them on the table. There were also two shirts, two pairs of underpants and two pairs of trousers.

‘These could come in very useful. But there aren’t enough.’

A drawer contained needles and thread, as well as other objects that I was unable to identify.

‘Scissors, buttons and zips—for repairing their uniforms,’ said Anthea.

That was all, which she found puzzling.

‘No photos, or letters, no personal belongings, but it’s true, they didn’t live here. They probably kept all that somewhere else. They left in such a hurry, they didn’t have time to gather their things.’

She broke off, frowning.

‘What’s the matter?’

‘But if they didn’t live here, why the shirts and the boots?’ She shrugged.

We crossed the room where the cans of food were kept to get to the cold store on the other side. Anthea stopped to check the thermometer on the door.

‘Minus fifty! This food was meant to last for a very long time. Maybe fresh supplies didn’t arrive all that often.’