During a regular after-school grub crawl, gluttonous high schooler Hibiki Sakura is confronted about her ever-expanding waistline by her best friend, Ayaka Uehara. With her attempts at solitary exercise failing miserably, Hibiki decides to join the newly opened Silverman Gym. At her orientation, Hibiki runs into student council president and school idol Akemi Souryuuin.
However, it soon turns out that Hibiki is in for a lot more than she bargained for. Not only is Silverman Gym full of world-renowned bodybuilders and athletes, but to make matters worse, Akemi turns out to be a total muscle fetishist! Grossed out by the scene unfolding before her eyes, Hibiki begins to leave, only to be stopped by trainer Naruzou Machio. Completely enthralled with her newfound Prince Charming, Hibiki signs up as a gym member. Now, as a result of her spur-of-the-moment decision, Hibiki must adapt to her new lifestyle.