Junichi Ieda is a popular, athletic high school student. He discovers classmate Noriko Yoshifuku's absence stems from compulsive sexual behavior, not illness. When visiting her home alongside classmate Satoshi Akiyama, Junichi initiates an intimate relationship with Noriko. He maintains friendships with both Noriko and Satoshi, navigating complex interpersonal dynamics. Junichi publicly defends their unconventional dynamic against classmates bullying Noriko about having two boyfriends, framing their connection as three friends supporting each other. His family includes a sister who develops romantic feelings for him, leading her to confront Noriko. This prompts Junichi to establish firm boundaries regarding sibling relationships while still offering his sister emotional support. Throughout these events, Junichi navigates a balance between physical confidence and interpersonal responsibility, addressing Noriko's needs and his sister's emotional turmoil while maintaining clear relational limits.