A married woman, Tsukimi Iori, comes to the gym to lose weight. Gym trainer Yoshida loves boobs more than food, and even though he thinks "You shouldn't look!", he can't help but stare at Tsukimi's boobs... After Tsukimi changes into her sportswear, Yoshida, while erect, teaches her stretching, muscle training, and the aerobic bike. Before he knows it, Tsukimi's sportswear is soaked with sweat that it's no longer worth wearing, and it becomes so see-through...