Ten years after returning to his hometown, Ayumi, a friend of his mother, reunites with her son, Seigo, who fondly recalls his first love. One night, a drunken Ayumi tempts Seigo with a kiss. Though initially hesitant, Seigo becomes increasingly aroused by Ayumi's bold advances. Later, he accidentally catches sight of her naked in the bathroom late at night and quickly flees in panic. But Ayumi visits his room, sparking an unexpected turn of events.