Machine

Three years after the battle with the Didact, the debris from Mantle's Approach come crashing onto Creation, a deteriorating human colony. And when Soleil, a young scavenger bent on getting herself off of Creation, stumbles upon an intact console, she isn't ready for what she finds.

Cortana thought she'd been lost to rampancy, but her skilled rescuer managed to patch her up and return her to her old self. And while Cortana is recovering, she receives an incoming signal from a passing Covenant ship. The Covenant are heading for Earth with the remaining Promethians, and they plan to take out the UNSC and the human race once and for all.

And when the Covenant trace Cortana's interception back to Creation, Soleil and the recovering AI then become their newest target. Now the two must find a way off of Creation and back to UNSC to warn Master Chief and the others of the incoming attack before it's too late.

There's just a few problems - Cortana isn't fully repaired, and Soleil has never fired a gun before in her life, let alone taken on an entire Covenant fleet coming straight for her. And, if they even manage to survive the attack, how will they even get themselves back to the UNSC Infinity?