Hideo Akai is a high school student sharing classes with Mew Fumizuki and Mica Minazuki. He discovers their secret identities as alien androids, the Hyper Dolls, extraterrestrial defenders of Earth. This knowledge puts him in constant peril due to their explicit threats to twist his head off if he reveals the truth, forcing him to live in fear of them.

Despite his reluctance, Akai is frequently entangled in the Hyper Dolls' activities. He is present during their battles against alien monsters and other threats but is forced to observe passively, unable to participate. This enforced bystander role fuels his feelings of helplessness and anxiety concerning the duo. Their relationship is characterized by coercion and Akai's lack of agency.

Another classmate, Shouko Aida, persistently tries to uncover the Hyper Dolls' secret. Shouko may harbor a crush on Akai, adding complexity to his school life. Bound by the Hyper Dolls' threats, Akai cannot disclose the truth to Shouko or anyone else. Akai's interactions with local authorities, such as Detective Toudou, occur indirectly through the Hyper Dolls' activities. The detective is an ardent supporter of the Hyper Dolls, a stark contrast to Akai's fearful and reluctant association with them.