A week before final exams, Fujimaki found himself with time on his hands. His girlfriend had gone away on a study camp with her clubmates. While heading home alone, he happened to run into Satomi Kawai. He and Satomi had a history of having sex after she sought his advice regarding his relationship with his girlfriend. Facing the risk of failing her exams, Satomi invited Fujimaki to her home to tutor her. However, being someone who simply loved sex, Satomi ended up devoting more time to erotic activities than to studying. The next day, he found himself talking with Satomi's mother while waiting for Satomi to return from her part-time job. Her mother bore a striking resemblance to Satomi, particularly in the way she leaned in close and engaged in excessive physical contact. Fujimaki became aroused by the mother, whose attractive figure was pressed right up against him. As a gesture of gratitude for tutoring her daughter, she seduced him by revealing her breasts.