In the distant future, humans have ruined their home planet, Terra, through careless environmental tampering. To preserve the life of their homeland, Terra, humanity has evacuated this world to spread life to other planets. Humanity, now governed by a supercomputer that controls childbirth, witnesses the rise of a new human race known as the "Mu," whose telepathic abilities have alarmed the System managing all of humanity. The Mu, now concealed from the rest of humanity, share one dream: to return home to Terra...