Humans have built a fully rational society in space in the 500 years since Earth's environment was destroyed and the planet became known as Terra. The government is run by supercomputers, kids are generated in artificial wombs and given parents at random, and youngsters take a "Adulthood Exam" at the age of 14. Humanity's greatest foe is the "Mu"—humans who have evolved into espers. When it comes time for Jomy Marquis Shin to take his Adulthood Exam on his birthday, he is surprised to find that all of his childhood memories would be deleted. Suddenly, he hears the voice of Soldier Blue, the Mu's leader, urging him to keep his memories safe. Jomy makes his getaway on a motorcycle.