Rin, returning home during the peak of summer, finds herself at her in-laws' house, neglected due to her father-in-law's hospitalization and her husband's work. One day, she meets neighbor Sakamoto and walks with him to his place. Intrigued by his shy reactions, Rin exposes her sweaty cleavage, steadily arousing him. Unable to resist any longer, the virgin Sakamoto pins her down and frantically pleasuring her until she climaxes repeatedly. Her visit home becomes consumed by their intense, sweat-drenched encounters, as she increasingly succumbs to his growing passion.