Nan-kilo moteru dumbbell ? - ダンベル何キロ持てる?
Sakura Hibiki is a greedy high school student, with a lot of appetite.
Seeing that her clothes start to tighten her more and more, and her best friend Ayaka Uehara who points out her weight gain to her, she decides to enroll in a gym.
There she meets the trainer Machio, and Akemi Sôryûin, a girl from his fetishist school for muscular bodies.