But in the end they had to get down to business.

‘Earthshine,’ Stef said simply. ‘That’s the top and bottom of it. Earthshine.’

Quintus Fabius said, ‘Earthshine. If I understand you, this is the – machine – that you brought with you from your old world, and is now on Mars—’

Kerys said, ‘I have had years to get used to these ideas, Centurion. You’ve had days. And I barely understand it. We’ll have to let them talk this through. And then, I suspect, we’re going to have to make our superiors understand too.’

‘I look forward to that, nauarchus,’ he said drily. ‘Very well – Earthshine. Tell me why we must discuss this.’

‘For one thing,’ Penny said, ‘he is the reason we are here. I mean, we survivors of the jonbar-hinge event, the destruction of the worlds of our own timeline …’

Quintus looked helplessly at Kerys. ‘Do they always talk like this?’

‘I’m afraid so.’

The ColU said, ‘The jonbar hinge came with a great surge of energy, when the UN-China war erupted, and the kernels on Mercury were opened by the Nail, the Chinese missile … Perhaps such a surge, involving kernels, is necessary to create a hinge. Meanwhile you, Stef, were with Yuri and myself in a Hatch, en route to Romulus-Remus. And you, Beth, Penny, were with Lex McGregor, fleeing the solar system behind a bank of kernels.’

Stef said, ‘You’re suggesting that somehow the kernels, the Hatches, preserved us.’

The ColU said, ‘Yes. I think Earthshine moved us to where he wanted us to be, like chess pieces on a board, Colonel Kalinski. At least the key pieces. Consider. Who survived the jonbar hinge? Earthshine himself. And his son, Yuri Eden. Or at least, the son of Robert Braemann, one of the input personalities that became Earthshine. And his granddaughter, Beth Eden Jones. Everybody Earthshine might have cared about personally—’

Mardina turned on her mother. ‘His son? His granddaughter? What new horror is this? That thing on Mars – are you telling me that it’s somehow my great-grandfather? Mother – did you know?’

Beth sighed. ‘I knew. He told me his name on the Tatania, as we fled from the moon. And my father, Yuri, told me his true name before we parted, on Mercury. And when I put the two together—’

‘You never told me?’

‘You’ve spent your life rejecting your past, Mardina. Are you saying you would have wanted to know?’

Quintus Fabius leaned forward. ‘I can see why this is difficult for you all. This talk of the past – but now we must speak of the future. Collius, tell us of the ice ball, the world you Brikanti call Höd. And the observations we have been making of Earthshine’s activities.’

Penny frowned. ‘ “We”? Who’s “we”, the Empire?’

‘No. We of the Malleus Jesu,’ the ColU said. ‘Academician, during the journey back I was privileged to work with the ship’s team of navigators and observers. They are Moslems, mostly Arab. A product of a high civilisation, though one subsumed within the Roman system in this timeline.’

‘I’m guessing you had them observe Ceres,’ Penny prompted.

The ColU said, ‘I had a feeling that the tracking of the object, and the projection of its future motion, might be beyond observers on Earth. Especially give the erratic pattern of the kernel-bank burns they are applying. You can’t be sure where it’s heading. I, however—’

Beth laughed. ‘With your superior computational powers, you know exactly what’s going on. You always were conceited, ColU.’

‘Liu Tao once said to me that for a farm machine I have ideas above my station. And I replied by pointing out that a sentient mind refuses to be confined by the parameters of its programming—’

‘Get to the point!’ Quintus was almost shouting now. ‘Where is this ice block heading, o engine of glass?’

‘Towards an impact on Mars,’ Penny said tiredly. ‘Am I right, ColU? Not a close approach, a grazing encounter with the atmosphere—’

‘I’m afraid you are correct, Penelope Kalinski.’

Stef nodded dumbly. ‘Very well. But why? What is he intending to achieve?’

‘I can think of only dire and destructive possibilities,’ the ColU said.

Quintus and Kerys shared grim glances. Kerys said, ‘And whatever else he does achieve, he’ll probably trigger a war, in the Skull of Ymir as on Terra. Rome and Xiu will probably believe this is some ploy by Brikanti, who sent Earthshine to Mars.’

Quintus turned to the slave. ‘What can we do, Collius? Can we stop this?’

‘Time is short,’ the ColU whispered. ‘It is fortuitous we arrived back here in time to observe this, let alone intervene. I would suggest that only Earthshine himself can stop the collision – if he wills it.’

Stef said, ‘Then we have to go there. To Mars.’

Penny said, ‘Why should he even speak to us?’

‘Maybe not to us. Which is why we must all go. Beth, Mardina – I know how difficult this is going to be for you – but you’re his family. If the ColU is right, he’s already saved you once. Maybe he’ll listen to you again. If there’s even a chance of averting this …’

Beth looked away, and Penny saw how closed-up she became, as, not for the first time in Beth’s life, those around her plotted to manipulate her and her daughter. Penny said gently, ‘Just think about it, Beth. The consequences of all this. We did bring this creature into this reality. We have to try.’

Stef said briskly, ‘But we’ll have to get to Mars first. How are we going to do that?’

‘In my ship,’ said Quintus Fabius firmly. ‘I am serious,’ he said in response to their surprised expressions. ‘The Malleus needs reprovisioning, but the crew have yet to be dispersed, and it stands ready to fly. My legionaries will squawk, but the journey would be short and the bonuses handsome, I imagine. I could have you all on Mars in days … If we can arrange suitable clearances quickly,’ and he glanced significantly at the shocked-looking provincial official.

Penny frowned. ‘Where is this ship of yours? In orbit, on the moon—’

‘About five kilometres north of here,’ Stef said drily. ‘This is a culture where they land interstellar spacecraft at city airports.’

‘I wish I could say you get used to such things,’ Penny said to her. ‘But you don’t.’

Mardina was looking around at them as they spoke, mouth open, obviously amazed by all she’d heard – overwhelmed perhaps. ‘Well, then, let’s all fly off to Mars, and find out the truth.’

Beth touched her arm. ‘What truth, dear?’

‘That that’s what this terrible old monster with the pretty name, Earthshine, probably intended you to do all along. That he’s been manipulating you all for decades.’

There was a shocked silence.

Then the ColU said, ‘Even I hadn’t thought of that.’

CHAPTER 26

The deceleration of the Malleus Jesu into Martian space was ferocious.

Nobody would tell Penny how high they ramped it up in the end. Clearly it was far higher than an Earth gravity, the Roman ship’s standard kernel-driven acceleration regime. That itself said something of the urgency of the mission. But Penny had little energy to fret, as she lay pressed down into her deep couch, scarcely daring to move a muscle, to lift a finger.

She was given a private room on the seventh deck, officer country – she was told it was part of Centurion Quintus’s own suite – a very Roman affair, though the couches were riveted to the floor and the tapestries fixed with heavy iron nails, and everything was sturdy, built to withstand the surges of acceleration to be expected of a warship. On the other hand the Malleus, veteran of several interstellar missions and as a result of cumulative time dilation several decades out of its own era, was an antique. The ship had already been subjected to years of acceleration, and the sleeting radiations and corrosive dust and ice grains of interstellar space, and now she was to be put through what in some ways was likely to be her toughest assignment yet. It might only take one component failure, a structural element buckling somewhere, a bulkhead or a hull plate cracking under the unbearable stress, for the whole mission to unravel – and their lives to be lost.