Swänn and Sätie were born on Näkän, a major planet in the Complex, a federation of extraterrestrial civilizations. The young couple hoped to live a peaceful life in an environment where nature and technology coexist in balance. But they are forced to mobilize when the leaders of the Complex decide to launch a vast expedition to save a planet that has exhausted its resources: Earth.

Swänn and Sätie, originally from the planet Näkän, have now been living on Earth for twenty years. They belong to the medical and military staff of Renaissance, the expedition financed by the Complex to rescue the Earth from ecological disaster. Most communities now live in harmony with their extraterrestrial saviors, while others have withdrawn into human enclaves in autonomous zones, where Swänn and his kind aren't welcome. More troubling for Renaissance, however, is the terrorist opposition that is quickly gaining steam, throwing a wrench into the gears of the benevolent occupiers. They will soon see that these humans are ready to do whatever it takes to get the Complex out of the solar system.

History is made with the first human expedition to another galaxy, under the guidance of Renaissance. Meanwhile, back on Earth, Liz explores the foothills of the Andes in a desperate search for Swänn, hoping to find him in one piece. An ocean away, in London, Hélène and Sätie follow the trail of a forbidden experiment: the creation of human-Näkän hybrids. Three expeditions, three paths that will lead to the discovery of the greatest threat ever orchestrated against humanity and Renaissance...