A guy name Sunao and a girl Kei, two good friends while they were children, are suddenly separated when he moves to a lunar city construction. A few years later, Kei has become an U.N. Investigator and she travels to the same base, without knowing anything about Sunao. But this is not just about them. Rich enterprises and dark men will want to own the new businesses that living in the moon will have, and soon Sunao and Kei will find troubles with them.