Dr. Narumi Narutaki operates on behalf of the Japanese government, aiming to reverse perceived declines in Japanese masculinity. His mission requires collecting 100 semen samples from specific male donors to complete research restoring traditional masculine strength. He recruits schoolgirl Marine Nonohara through deception, forcing her compliance via an unremovable ring and a costume that adapts to each man's desires; the costume binds her until all samples are collected.

He deploys a robotic turtle that implants itself inside Marine to safeguard her virginity during collection. This device retrieves semen directly from her womb post-intercourse, storing it. Dr. Narutaki justifies these methods as necessary for national preservation, though his aggressive approach and sanity are frequently questioned.

His plans face disruption due to betrayal by his assistant, Dr. Marilyn Willow. Motivated by a personal grudge over past romantic rejection, she develops a rival android, South Pole One, designed to collect semen more efficiently while eliminating donors. This betrayal sparks direct competition between Marine and the android, with Dr. Narutaki opposing Marilyn's efforts.

Despite his manipulative tactics, Dr. Narutaki displays intermittent concern for Marine's well-being, ensuring her physical protection through his inventions. His background remains unexplored, though his grey-haired, black-eyed appearance in a lab coat fits the eccentric scientist stereotype. The project concludes inconclusively after South Pole One destroys the laboratory and escapes with Marilyn, leaving Dr. Narutaki's success uncertain and his research incomplete.