The only thing that motivates a specific sixteen-year-old boy to wake up early on Sunday mornings is the weekly airing of his beloved show, Magical Girl Pretty Eririn (PreEri). However, Rio Aoi is ashamed of his love for children's anime and attempts to avoid contact with his classmates, only leaving school for the occasional PreEri merchandise shopping trip. This mundane routine is interrupted when Aoi saves a girl named Nagi Sumire, who happened to fall from the sky while battling a monster. The next day, Sumire introduces herself as a magical girl who lacks confidence and Aoi accidentally reveals his knowledge of PreEri to her. To his surprise, Sumire reacts excitedly and asks Aoi to teach her about magical girls, thus beginning a supportive friendship and rigorous training.
