One thousand years from now, aliens destroy Earth in fear of the Titan project. Some humans escape, becoming a downtrodden Diaspora, living in impoverished settlements. The mysterious Titan spacecraft also escapes, and its inventor has hidden it before dying. A spacecraft captain and its pilot, Korso and Akima, two humans, seek out Cale, the youthful son of the dead scientist and explain that he must help them find the Titan, which holds a mechanism to unite and save humanity. Cale refuses, but the arrival of the killer aliens persuades him to join Korso. Can he avoid his pursuers, know friend from foe, find the Titan, and embrace his humanity, a nature he has despised until now?