Kameda, a university student, has just gotten his first girlfriend. Although Kameda is a shy person, he decides to confess his feelings and his feelings come to fruition. His girlfriend, Suzu, is also a quiet and innocent girl... or so he thought. On the day Kameda first comes to his house, Suzu starts having sex with a neighborhood middle-aged man right in front of Kameda, as if it were the most natural thing in the world. Kameda is shocked by the sight, but ever since then he has been at the mercy of the lustful Suzu, who seems to have no sense of chastity...