250 years ago, humanity nearly destroyed itself in the Great War. Shortly before, a spaceship full of researchers and astronauts had found a new home on Saturn's moon, Titan, and survived by having their descendants genetically adapted to the hostile environment.

The Titanians, as they call themselves, are proud of their cooperative and peaceful society, while unbeknownst to them, humanity is slowly recovering back on Earth. When a 20-mile-wide chunk of rock escapes the asteroid belt and appears to be on a collision course with Earth, the Titanians fear it must look as if they launched the deadly bombardment. Can they prevent the impact and thus avoid an otherwise inevitable war with the Earthlings?

2312: In the first-ever terraforming program, millions of drones are repairing the home of humanity, which had been rendered virtually uninhabitable by the Great War of 2299. Megacorporation Olympus manufactures and controls the autonomous repair swarms, and is building a widespread mining system in the asteroid’s main belt to harvest the resources urgently needed to restore Earth.

When the control center on Psyche loses contact with an automated mining station in the main belt, Olympus hastily assembles a small team to reboot the errant software. As soon as they land on the asteroid, Sara Renberg and her two teammates discover they are in the grip of a mysterious and powerful force – and Earth itself is the target of a devastating attack!