Haruka feels lonely with a husband who shows no interest in her, making Yoshino and their monthly sex deeply important to her. One day, he suddenly asks whether she has ever been on a track team. Her body is lean and beautifully curved, but she has no experience at all. After hearing her answer, Yoshino hands her a uniform and orders her to call him Coach. Though hesitant, Haruka is terrified of losing him, so she agrees to join his filthy, perverted adult track-team role-play and obey his every command.