Titus grunted, pointing to the dome. ‘So our long journey is over – and there is the obvious destination. We should be ready to defend ourselves.’

The ColU said now, ‘You may be right, legionary. But consider this. Earthshine needs no such shelter as that dome, whereas you do need shelter. Perhaps the dome itself should be seen as a gesture of welcome.’

Titus nodded cautiously. ‘I see your reasoning. But consider this, in turn. If we would be welcome, so would Ari and Inguill have been, if they got this far. We should be prepared for whatever they are up to in there. Also, if Earthshine, or his image, could walk around on this ice butt-naked—’

Beth laughed. ‘Titus, he could fly through the air if he wanted to.’

‘Then why isn’t he here now? I’m quite sure he’s as aware of us as we are of him. Why not come out and see us?’ Titus glanced around at the group. ‘It’s clear that there’s much about this situation that we don’t yet understand. We go to the dome. It’s the obvious destination. The only destination. But we go in with our hands open in gestures of peace and friendship, and our weapons sheathed at our backs. Agreed?’

Stef shook her head. ‘You’re a terrible cynic, Titus Valerius. And I’d like to see you in a knife fight, you’re like an overweight panda in that cold weather gear … But you and your instincts have kept us all alive this long. Agreed.’

They formed into a loose party, with Titus, Chu, Clodia and Beth hauling the cart towards the dome, and Mardina walking with Stef at the rear. Titus and Chu were in the front rank, and Stef could see their pugio daggers tucked in the back of their belts, glittering in Andromeda light.

Mardina linked her arm through Stef’s, and they walked cautiously together. Stef peered up. ‘That sky isn’t what it was when I came this way before, with your grandfather Yuri, in that other timeline. It’s been so long, the stars have swum around the sky, or aged and changed, the constellations have all melted away. I thought I would still be able to see her, though, up at the zenith. Brilliant she was, and as we walked to the antistellar we saw her steadily rise in the sky unlike any star.’

‘ “Her”? Who are you talking about, Stef?’

‘A creature called Angelia. A creation of my father.’

‘Another artificial person, then. Like the ColU, like Earthshine.’

‘Yes. Actually she was also a kind of ship. She and her lost sisters … I got to know her. I don’t suppose she could have survived this long. Why, in a billion years or two her very substance would have sublimed away, probably.’

Mardina squeezed her arm. ‘We’re in another history. She was probably never here at all.’

‘Maybe not,’ Stef said with a bitterness that surprised her. ‘Just another story, erased by the Dreamers’ meddling.’

‘No, not erased. Not as long as you remember her.’

Stef felt unreasonably touched. She patted Mardina’s hand. ‘You’re a good person, Mardina.’

Mardina laughed. ‘Despite my great-grandfather being a criminal mastermind downloaded into a box of metal and glass?’

‘Yes. That’s quite a legacy, isn’t it? But Yuri at least was a good man, your grandfather, I can tell you that much. And you’re going to make a fine young mother.’

But that was the wrong thing to say. Stef could feel Mardina stiffen.

‘Well, there’s not going to be the time to find out, is there? Not if the ColU is right that all this—’ and she gestured at the starry sky ‘—is about to roll up like a closing scroll.’

Stef could think of nothing to say.

She was relieved when Titus, in the van of the party, reached the translucent wall of the dome.

CHAPTER 69

The dome was perhaps fifty metres across, Stef estimated as they walked around it, maybe ten metres tall at its midpoint, the highest point. Its skin was reasonably clear, translucent, and she saw no signs of support, no framework, no ribbing.

Titus glared in through the wall, as if he was scouting out the war camp of a bunch of unruly barbarians. Well, perhaps that wasn’t so far from the truth. He pointed out structures within the dome, piles of materiel. ‘That looks like what might have brought Ari and Inguill here.’ A sled, much smaller and cruder than theirs, with heaps of garments and blankets roughly dumped around it – heavy coats, thick boots. ‘And that object in the centre, a kind of pillar in the middle of a mesh framework—’

‘I believe that is Earthshine,’ the ColU murmured. ‘His support unit anyhow. But evidently heavily modified, for some purpose. And, over there …’

They could all see what it meant. At one side of the dome was a Hatch emplacement, set into the rocky floor.

Stef cupped her hands around her eyes and peered in through the wall, trying to see better, cursing the vapour that rose up from her breath. A Hatch like any other Hatch. Just like the one she’d been brought to on Mercury, the first she’d seen – like the one Dexter Cole had found here on Per Ardua, right here at the antistellar – just like the Hatches she’d seen on worlds of other stars. All of them were alike, just a rectangular panel a few metres across set in the ground, the fine circular seam that marked the position of the lid. Crude functional simplicity.

Yet these simple gadgets were responsible for altering history itself, for adjusting the destinies of billions of souls. Stef was a physicist, and she’d been studying Hatches most of her adult life. Still they made her shudder.

And on this particular Hatch that lid gaped open.

‘So,’ the legionary snapped. ‘Now what? Do we cut our way in?’

Clodia pointed. ‘Either that, Father, or follow the arrow on the wall.’

They came to a doorway, a blister that protruded from the smooth dome wall.

Titus said, ‘This door has a handle; that’s simple enough.’ He squinted through the wall. ‘And a second door within.’

‘I think it’s a kind of airlock,’ Stef said, surveying the dome again. ‘This structure has no internal skeleton. Has to be air pressure holding it up. Se we need to go through these double doors to avoid letting out all the inner air, and the warmth.’

Titus said sourly, ‘I have served on starships, you know; I do know what an airlock is. Not that I was expecting to find one here. The practicalities concern me more. Such as, I doubt if this lock could take more than three of us at a time. Two, if laden with baggage. We’ll have to be separated to enter.’

‘I sincerely doubt there will be any threat,’ Stef said briskly. ‘Legionary, you can see through the wall. There is only Earthshine … Even Ari and Inguill are nowhere in sight. I think we can take the risk, don’t you?’

‘And I for one,’ said Beth, ‘am keen to get out of this cold, for the first time in weeks.’

‘Lead us, Titus Valerius,’ Stef said.

It proved simple enough for Titus and Clodia to cycle through the airlock. Experimenting, Titus found there was a failsafe. ‘The inner door won’t open unless the outer one is firmly shut,’ he boomed, his voice muffled by the thick dome wall. ‘The air within is warm and moist.’ Still inside the airlock, he pressed his hand against the material of the dome. ‘This is pliant, yielding a little, but evidently thick and strong. It will be interesting to see how it withstands the blade of my pugio—’

‘Not now, Father,’ Clodia said. ‘Come on.’ She led the way through the airlock’s inner door and into the interior of the dome, pulling open her heavy clothing as she walked.

Stef took Mardina’s hand, and they both stepped into the airlock together, leaving Chu and Beth unloading stuff from the sled. Mardina closed the outer door, and Titus opened the inner for them – and, just as Titus had described, warm, moist air gushed over them. Stef took deep, shuddering breaths, already feeling warmer than she’d been since crossing the terminator.