Stranded on the Moon without enough food, parents in two competing bases try to save their children by sending them to Mars on an aging spaceship. The trip takes longer than the supplies last. As food runs out, the social order crumbles and factions form. Keiron Byrne (12 year old cousin to series protagonists Cas and Ori Byrne-Alli), Ro Cook (14 year old crush, bully, and eventual nemesis of Keiron), and Jun Tian (12 year old prodigy from the opposing base who has a secret that might save them all) must navigate starvation, racism, betrayal, and a ship that is beginning to behave very oddly.