‘Listen, child. The sole purpose of the Guardians is to serve humanity. But what is humanity? Since the Guardians were first installed we humans have bifurcated, innovated, rebuilt and re-engineered ourselves. Even the stock who remained on Earth and Mars, like your own family, has adapted in its own quiet way. Each of these subtypes is “human”, in that they can all trace their ancestry back to the common root. But none of them is identical to the root stock. And a biologist’s definition of humanity isn’t necessarily good enough for a weapons system.’

‘Ah.’ The Curator nodded. ‘The Guardians are so old they no longer recognise the much-evolved descendants of their makers as human at all. Not even you, old one! What an irony.’ He shook his head and laughed.

Luru ignored him. She said to Symat, ‘I have found a solution for Earth - and I need the Guardians’ help to implement it. But they won’t listen to me. I needed a true human, Symat, at least “true” in the discriminating eyes of the Guardians. And, as I was unable to find one, I had to breed one . . .’

Genetic engineering had been considered. Even if nobody like the ur-stock of humanity still existed, there were records of their biomolecules. But the Guardians would easily have been able to spot any such engineering; they would have rejected the wretched result as a fake.

So Luru had had to resort to more natural methods. She had surveyed the human population of Sol system. She had identified stretches of raw DNA in fragments, scattered over the worlds. And she had begun a programme of patient cross-breeding, seeking to gather together the strains she needed.

It took a thousand years. But a millennium was a moment for an undying.

‘And it all culminated in me,’ Symat said.

‘I told you you’re different, Symat!’ Mela said. ‘No wonder you don’t look like your parents. And no wonder the Conclave was watching you.’

‘You probably don’t look much like an ur-human either,’ Luru said dryly, ‘but I think you’ll fool the Guardians. And that’s all that counts.’

The Curator said, ‘And did these generations of toiling breeders know how you were using them, Ascendent?’

‘It was safer for the project that they didn’t. A little social engineering sufficed.’

‘And this is your master plan? After a galactic war and a million years of history, the future of man comes down to the decision of a fourteen-year-old child? . . . Lethe, Ascendent, what gives you the right to make a choice that will fix the whole future of mankind - even through this boy?’

‘Only I have the vision for such a solution,’ she murmured. ‘Only I have the longevity to see it through. That’s what gives me the right.’

Symat said, ‘What would I have to do?’