Kazuto Iizuka is an ordinary 14-year-old boy. That changes when he encounters another student at his school, Narue Nanase, who saves him from an attacking alien creature. During the ordeal, Kazuto discovers that Narue is actually half-alien and that her father is part of a galactic exploration team. Encouraged by his friend Masaki Maruo, Iizuka asks Narue out on a date. Narue is reluctant at first, but after Kazuto assures her that he is not bothered by her alien heritage, Kazuto and Narue begin their relationship as boyfriend and girlfriend. However, like any couple, they have to deal with their fair share of problems; such as Narue's alien sister Kanaka and Hajime Yagi, Narue's classmate and ufologist who doesn't believe Narue is really an alien and thinks that Narue is lying to get attention.