A year after a traffic accident left her with a permanent disability in one leg, high school student Yori is repeating her first year. The injury ended her involvement in少林寺拳法 (Shorinji Kempo), an activity she once loved, and left her struggling with feelings of inadequacy. She keeps a distance from her classmates, who are all a year younger, and finds solace in her "oshi-katsu" – devoted fandom of a popular shonen manga called Hogyoku Gakuen. Into this isolated routine steps Yayoi, her childhood friend from ten years ago. When they were children, Yori had protected the small, crybaby Yayoi from bullies, and they had made a childish promise to marry each other.

But the boy who returns is no longer the vulnerable kid she remembers. Yayoi has grown into a strikingly handsome, athletic, and academically gifted young man. He is immediately forward and possessive, declaring his intention to marry her and pursuing her with an intense, single-minded devotion. Yori, still processing her trauma and lacking confidence, is overwhelmed by his forceful approach. Despite her resistance, Yayoi's unwavering support gradually begins to break through her walls.

Their relationship deepens through a shared love for Hogyoku Gakuen. Yori sees herself in the character of Makito, a prince who loses his claim to the throne due to an injury. Yayoi connects with her by making handmade plushies of her favorite character and eventually engaging in cosplay with her. This shared interest also brings in Yayoi's uncle, a popular cosplayer, creating a new dynamic and source of jealousy. As Yayoi's sincere, heavy affection chips away at the barriers Yori has built around herself, the story follows her tentative steps toward healing, opening her heart again, and learning to accept love and support from someone who has always seen her as his everything.