Kojima has recently become physically sluggish due to lack of exercise. His boss's wife, Toko, invites him to train together. Unconsciously drawn to her, Kojima can't help but get aroused by her toned physique. Toko, a married woman who hasn't had sex with her husband in a long time, is tempted by Kojima's strong desire and shyly gives in. From that moment on, their lust knows no bounds.