Milton is stressed. He's only got twelve minutes to download the story of humanity and the Habitat mission. What should he include? Does he dare omit anything? Armed with only a three thousand word vocabulary and rudimentary emotions, how can he, an android, possibly relate the depth of emotions he's witnessed over the thousands of years of traveling? His saga begins in the 22nd century when Earth is about to be destroyed. At the instigation of a mysterious alien species, a handful of scientists and moguls build Habitat to save fifty humans and preserve cultural achievements spanning continents and recorded history. As they head towards their rendezvous with the aliens, the social rivalries and violence of Earth inevitably find their way onboard, and all hell breaks out. In the end, much of Habitat's enormous Archive is destroyed, with only five humans and ten clones of a 17 year-old wunderkind, Mars Walking Moon, surviving-and Milton, who's left in charge of the teenagers after the adults are put into hibernation until the rendezvous. Now that the encounter is imminent, he tries to relate the chronicle of the last humans, especially the supposedly identical teens, who prove to be anything but-hardly alike and often frustratingly complex beyond their years. His attempts to understand them and the human condition raise countless questions about humanity's place in the vast scheme of the universe. In the end, will the mysterious aliens for whom he's downloading his epic tale help him achieve answers and closure?