The flitter swooped away from Saturn, climbing up and out of its deep gravity well, the energy of its incoming trajectory dumped. And the Curator showed Symat how to look for the moons.

Spacegoing mankind had swept like a storm through Sol system, shattering in a few millennia the patient geological assemblings of aeons. Saturn’s ice moons, if not taken apart altogether, had been extensively mined. One moon was more interesting, though. The Curator called it ‘Titan’. Once this small world had had decks of clouds beneath which complex chemical processes had played out; humans had sent scoop-ships and trawlers to mine the air and the hydrocarbon seas. But Titan, starved of heat, had never spawned life. Now, as the sun brightened, Titan was at last stirring from its chill slumber. It was a marvellous prospect, the birth of a new world right in the middle of Sol system: even in these desolate latter days you could still find new life. But no human scientists were studying the miracles unfolding in Titan’s clouds. This was not an age for science.

They left Titan behind. And as the flitter continued to swoop around Saturn’s gravity well, the true human purpose of this system was gradually revealed.

‘Can you see?’ The Curator ducked and pointed, picking out lights scattered among the moons. ‘And that one? They are drones. Sensor stations, weapons platforms. All sentient.’

The sky was full of them, machines that flocked like metallic birds in the ever-changing gravity field of Saturn and its moons. Some of them gathered into rings that girdled Saturn’s equator, which the Curator wistfully said were an echo of an even stranger wonder of the past, natural rings of ice and dust that had long been disrupted by war. And once you could have seen even more spectacular artefacts, the ruins of wormhole mouths, the remnant of a transit system that had once spanned a Galaxy but had collapsed with the demise of its builders, the Coalition.

But Symat understood that the beauty of the weapons clouds wasn’t their point. Their purpose was lethality. The whole of the Saturn system was a fortress. And it was all because of the Ascendents.

When the vast retreat of man had begun, even when only the most remote of colonies had yet been evacuated, the undying with their eerie far-flung prescience had planned the end game. Before the siege of Earth itself began, it would be necessary to make a stand.

Saturn had always been a military stronghold. As long ago as the Exultants’ heroic effort to win the Galactic Core, huge war machines had been buried in the planet’s deepest clouds, ready to leap to the defence of Earth if any foe dared attack the capital planet. These brooding machines, self-maintaining, self-enhancing, became known as the Guardians.