In 2163, a polluted and overcrowded Earth forces humans to search for a new home. But the exoplanet they target, Exilon 5, is occupied. Having already begun a massive relocation programme, Bill Taggart is sent to monitor the Indigenes, the race that lives there. He is a man on the edge. He believes the Indigenes killed his wife, but he doesn't know why. His surveillance focuses on the Indigene Stephen, who has risked his life to surface during the daytime. Stephen has every reason to despise the humans and their attempts to colonise his planet. To protect his species from further harm, he must go against his very nature and become human. But one woman holds a secret that threatens Bill's and Stephen's plans, an untruth that could rip apart the lives of those on both worlds.