This is the Nanoha spinoff that puts down the magic staffs and just lets two girls hit each other until the truth comes out. Fuuka and Rinne left the same orphanage carrying the same wound, and only one of them turned it into a fist, which is why the Winter Cup arc lands less like a tournament bracket and more like a court date. Einhard Stratos and Nove Nakajima coaching Fuuka out of a life of scraping by is the rare training montage where the point isn't power levels, it's someone finally telling a kid she's worth feeding. And Rinne is no villain, just a girl who learned that strength stops people from hurting you and never learned where to put it down. When they finally stand across from each other in the ring, the punches are an apology neither one can say out loud.

Fuuka and Rinne grew up together in the same orphanage and were once close friends, until a quarrel ended with Rinne overpowering Fuuka with her martial arts and the two went separate ways. Rinne was adopted and became a prominent martial artist, while Fuuka left the orphanage and scraped by in poverty, often getting into fights. After Fuuka is hurt in a clash with gangsters, champion fighter Einhard Stratos finds her and takes her to a hospital. Seeing real ability in her, Einhard offers her a job at Nakajima Gym and urges her to compete. Fuuka refuses at first because of painful memories, but she soon accepts and begins training, driven by need and by a wish to beat Rinne and show her how hurtful she has become. The action sports drama builds toward a rematch between the former friends in the ring.