In the far future, a thousand people are the only survivors of humanity, as Earth has been destroyed by an asteroid. Aboard a generation ship headed to a new solar system, a young Japanese man recounts the defining moments from his childhood.

A woman on a generation ship is offered the chance of immortality, and ultimately lives long enough to become part of subsequent 'waves' of human evolution - from man, to immortal, to machine, to pure energy - over countless millennia.