The novel is set in the distant future as a group of space travellers, marooned in an inhospitable planetary system, attempt to terraform a moon and create a sufficient civilisation on it to refuel their ship so they can continue to their original destination.

A couple of centuries from the present, artificial intelligences and nanotechnology are in widespread use in the Solar System and in some cases have caused disasters.

Three sleeper ships leave the Solar System bound for Ymir, using suspended animation to keep the crew and settlers alive during the sub light-speed journey.

The lead ship, John Glenn, is crippled by a design flaw en route, and uses all its antimatter fuel to reach the nearest star system, Apollo.

Rachel comes to realise that when the moon-born have helped restock the ship with antimatter the John Glenn will continue on to Ymir without them, leaving them on a moon that can only sustain life for a century or two.

Problems with radiation flares intervene, and without Gabriel to stand up for her, they are left frozen for twenty years.

Ten years after Rachel was unfrozen, an accident leads to a Council member shooting one of the moon-born.

A final, short, section of the novel sums up the next two hundred years, with the antimatter refined, the flare problem on Selene permanently dealt with, and John Glenn preparing for departure.