It?s 2094. Doctor Andrew Jackson, an astrobiologist, has perfected a hibernation process that will allow humans to travel to the far reaches of the solar system. He persuades World Dynamics Inc., the world's largest aerospace conglomerate, and the United World Council to co-sponsor an expedition to Pluto. There's only one catch. The trip to Pluto will take four years, longer than anyone has ever hibernated. Andy agrees to be sealed in a capsule and goes underground to prove his system works, but an earthquake in 2097 causes Andy's capsule to go missing. He is rescued many centuries later by an advanced race of humans who call themselves the Unoites. The Unoites live in the shadow of a profound mystery: that Pluto's two small moons, Hydra and Nix, are not moons at all but artificial satellites?placed there by whom? When? Andy is discovered by Phoebe, the Unoites? lone, sentient artificial intelligence. His awakening and acceptance by the Unoites allows Phoebe to gain new insights into the Pluto Enigma?but will she be able to share her new knowledge with her human friends?