Saki Uno, a fifteen-year-old member of the unpopular idol group Magical Twins, lives an ordinary life with her best friend Sakuyo Mikage and secretly harbors feelings for Sakuyo's brother, Mohiro. Her daily routine is thrown into chaos when a yakuza-like intruder tries to break into her house. After letting him in, Saki discovers that her mother was once a Magical Girl who fought demons, and the intimidating visitor is actually Kokoro-chan, a mascot searching for a successor. Though doubtful at first, Saki is convinced when Kokoro-chan reveals that Mohiro is threatened by cute, squirrel-tailed demons.
Determined to save Mohiro, her strong wish to protect him unlocks her Love Power, and after a bold confession, she transforms into a Magical Girl. Because her physique is unsuited for combat, her transformation results in a muscular male body adorned with a frilly dress. As a full-fledged Magical Girl, Saki joins forces with Sakuyo to protect her beloved from the adorable yet dangerous demons threatening their world.