Hazumu Osaragi, a shy and effeminate high school student, experiences a life-altering event when an alien spaceship accidentally kills him during a failed landing. The aliens, feeling responsible, reconstruct Hazumu's body but mistakenly revive him as a female due to a misunderstanding of Earth's biology. This transformation forces Hazumu to navigate a new identity while grappling with the reactions of those around them.

Hazumu's childhood friend, Yasuna Kamiizumi, who has long harbored romantic feelings, becomes even more attached to the now-female Hazumu. Meanwhile, Tomari Kurusu, another close friend and a tomboyish figure, struggles with her own feelings, torn between her affection for Hazumu and her discomfort with the sudden change. The series explores the complexities of gender identity, relationships, and societal expectations as Hazumu adjusts to their new reality.

The narrative delves into the emotional and psychological impact of Hazumu's transformation, examining how it affects their relationships with Yasuna, Tomari, and other classmates. The aliens, who remain on Earth to observe Hazumu, add a layer of science fiction to the story, occasionally intervening in subtle ways. The series balances moments of lighthearted humor with deeper, introspective themes, creating a nuanced exploration of identity and love.

As the story progresses, Hazumu's journey becomes a focal point for examining themes of acceptance, self-discovery, and the fluidity of gender. The interactions between the characters drive the plot forward, with each individual's perspective contributing to the overarching narrative. The series concludes with a resolution that emphasizes personal growth and the importance of understanding and embracing one's true self.