He and his girlfriend Hoshimi meet Lipmira, a woman from outer space, who tells Gen that he is the "mapman", meaning the map to a great treasure is coded in his genes.

Gen and Hoshimi leave Earth with Lipmira to find the treasure, a quest shared by evil space people whom they are often compelled to fight against.

[1] Notable aspects of the series are the spaceships (which look like giant silver angelic women, often described as "hood ornaments") and the robot women that control them, or more precisely embody them for dealings with regular-sized life forms (Lipmira is one of these robot embodiments).

The first, Maps: Densetsu no Samayoeru Seijintachi, was produced by Studio Gallop, directed by Keiji Hayakawa, written by Kenji Terada, and musically scored by Kohei Tanaka.

The second, simply titled Maps, was animated by TMS Entertainment, directed by Susumu Nishizawa, written by Masaki Tsuji, and musically scored by Masahiro Kawasaki.