Gnaeus nodded to the crewman operating the projector. The screen turned glaring white as the slide was removed, to be replaced by another, much more blurred, evidently magnified. The boot shape of Italy was clearly visible, even though, Stef thought, trying to remember detail, it looked to have been extensively nibbled back by sea-level rise, even compared to what she remembered from the Roman reality. The peninsula was carpeted by the usual network of industrial activity, and Stef tried to map the brighter nodes on the locations of familiar cities.

Gnaeus pointed to a dark patch near the west coast. ‘This is Rome. The image has been greatly enlarged, as you can see … Sir, we would have to move in closer to do much better than this.’

‘That can wait, optio. The area of darkness, you say—’

‘At first we thought there was some kind of quarry there. Then we realised that the site of Rome is encompassed by a crater, big enough that it would not disgrace Luna. And in the interior of the crater – nothing. No life, no industry.’

‘I reckon we can see what’s gone on here, sir,’ said Titus Valerius. ‘Some of the lads have talked it over. If I may speak, Centurion—’

‘You already are speaking, Titus.’

‘They bombed us, sir. Whoever runs this world. There must have been a war, and they drove us back, and when there was nothing left of us but the mother city herself, they bombed us.’ He rubbed his chin. ‘Maybe they dropped a rock from the sky. Or maybe they used kernel missiles. Making sure Rome would never rise again.’ His voice grew more thick, angry. ‘These bastards did to us what we did to those Carthaginians, long ago, sir.’

‘I fear you’re right, Centurion. The question is who these “bastards” of yours are.’

He seemed to hesitate before speaking further. Stef wondered how the ordinary Romans on this ship had taken the news of the loss of their eternal empire – how the likes of Titus Valerius had coped with such torment of the soul. Rome – gone!

‘Very well. Carry on, optio.’

‘Luna is missing,’ Gnaeus said now, bluntly.

That startled Stef. ‘What do you mean, “missing”?’

‘I’ve got no images to show you … It simply isn’t there. We know that must have distorted Terra’s tides and so on but we’d need more study to understand that fully. Maybe it was destroyed in some war. We made a mess of Luna when we fought the Xin up there. Our best theory, given the level of industrialisation on Terra itself, and the massive colonisation of space – I’ll discuss that – is that Luna was dismantled for its raw materials.’

He showed more slides, more worlds with faces disfigured by massive industrial operations, more carpets of glowing light. ‘All the rocky worlds are the same, sir. Mercury, Mars. On Venus much of the atmosphere is gone, and some kind of huge operation is going on under the remnant clouds – we don’t know what they’re doing there.’

‘And on Mars,’ the ColU put in, ‘the observers detected a kernel bed. A primordial deposit of the kind we found on Mercury, Stef Kalinski, though not on our copy of Mars.’

Knowing the ColU’s own obsession Stef prompted, ‘And where there’s a kernel bed—’

‘There’s probably a Hatch.’

The ColU said no more, but Stef understood. Some day we need to get to Mars, and through that Hatch, in pursuit of Earthshine. But, looking at image after image of worlds transformed by industrialisation – Gnaeus even showed huge mines on the moons of Jupiter – and given the power and reach of a civilisation that had gone so far in mastering their whole solar system, she wondered how and when the chance to do that might ever come.

Quintus said, ‘So we have a solar system of integrated industrialisation, of intense use of material resources, and, I presume, energy.’

Gnaeus nodded. ‘Mostly kernel-based, but not entirely; we’ve seen sunlight captured by huge sails. There are tremendous flows of raw materials, mostly from the asteroid belt inward to the inner planets. Evidence of widespread organisation and control. And we see no signs of current conflict, incidentally. As if all this is run by a single, unitary government. One empire, sir.’

Quintus snapped, ‘Whose empire? Who’s benefiting from all this? And where are they? The planets, even Terra, barely look liveable.’

‘Save by toiling slaves, probably,’ said Titus grimly.

‘Cities in space,’ Gnaeus said now. ‘That’s where we think the people must be. Cities – or fortresses. We had a few such settlements, habitats capable of supporting life. Observation platforms, docks for spacecraft and so on. The Xin too.

‘But here, wherever here is, the sky is full of them.’

He produced images of structures in space, grainily realised, cylinders and spheres and wheels, and some more angular structures.

‘They cluster around the major planets, or trail them in their orbits around the sun. And they come in all sizes, from units the size of small Roman towns, Centurion, to much larger. There may of course be smaller constructions below our ability to resolve. Some of them, near the asteroids or planets, may be habitats for workers: construction shacks. Others may be the equivalent of military camps, permanent forts – and cities, places of government and administration. We can only guess, for now. We have barely begun to study these objects. One thing that might help us, sir. The smaller habitats are very diverse. There’s a variety of designs, technological strategies. And although this “Quechua” is their dominant language, evidently the official one, we hear scraps of many other tongues – including bits of Latin.’

Quintus scowled. ‘So how does that help us, exactly?’

‘We can hide, sir. If we have to. Or at least be camouflaged. Some of those habitats and ships are not unlike the Malleus in size and shape.’

Quintus waved his hand. ‘I take your point, optio. And given the challenge of the bookkeeping of an empire on this scale, if it’s anything like our own, there will be room for concealment.’

‘That’s it, sir. And then there’s the big one, the one we’ve been calling the Titan. At the very top end, only one of a kind, the largest structure we have observed in the system by far … The big beast resides in a Shadow of Terra.’

‘He means, it’s at L5,’ the ColU told Stef. ‘Trailing Earth at a Lagrange point.’

Quintus waved his hand. ‘You’re beginning to bore me, oracle, and not for the first time. Show me that big monster, optio.’

Gnaeus obeyed.

It was a blunt cylinder, its exterior scuffed, returning muddled highlights from a distant sun. This was shown against the background of the self-illuminated Earth.

Quintus drifted to the front of the room to inspect the ‘Titan’ more closely. ‘That doesn’t look so special. Looks a bit like Malleus, in fact.’

‘It’s a little bigger than that, sir. You’re not grasping the scale of this thing – with respect, Centurion,’ he added quickly. ‘We’ve made guesses about its layout. It is spinning, around its long axis, not quite three times an hour.’

‘To provide spin weight inside that big ugly shell.’

‘Yes, sir. We’ve seen ships approach, along the long axis, where there must be docking ports.’ He pointed. ‘Just there, in fact.’

Quintus frowned. ‘I see no ships. Must be tiddlers.’

‘Sir, there are plenty of vessels larger than the Malleus itself; we see them coming and going … You still don’t see the scale.’

‘Tell me, then, you posturing fool.’

‘Centurion, the cylinder is nearly three thousand miles long.’

‘Three thousand—’

‘That is more than the diameter of Luna, sir. The end hubs alone could swallow a small moon. The land area within must be similar to that of the whole of Asia …’

Titus Valerius, muttering a blasphemous prayer to Jupiter, floated before the image of the great habitat, inspecting it more closely, casting shadows on the screen. He pointed to a blemish on the hull. ‘By God’s bones. That looks like a crater.’