Wife Iori Tsukimi started going to the gym to lose weight. Aiming for better health, she began receiving personal training from fitness instructor Yoshida. However, Yoshida has a weakness—he loves breasts more than food—and he can't help but stare at Iori's cleavage. As he guides her through stretching, strength training, and aerobics on the exercise bike, his gaze lingers on her in her workout clothes. Her sweat-soaked athletic wear gradually becomes see-through, eventually rendering it pointless to wear anything at all. As their sessions continue, the intimacy between them grows deeper and deeper.