Kana is a married woman who works as an instructor at a rural gym. Her relationship with her husband has cooled, but she hides this fact from the people in the neighborhood. Then, a middle-aged man named Ippei starts going to the gym after being introduced to him by a wife. As she teaches him day by day, Kana is attracted to Ippei and seduces him with her toned body. Feeling a sense of immorality as an adulterous affair unfolds in the town, Kana and Ippei become deeply involved...