Miyuki Nonogusa attends an academy where she joined the swim team in her sophomore year, displaying swimming talent that sparks envy in team captain Shinobu Kobayashi, contributing to her victimization. She shares a history with classmate Taki Minase, who bullied her in high school by calling her "Nogusa"—a crude term implying defecation outdoors—establishing a pattern that foreshadows later events. Her most significant incident unfolds in the school pool's locker room when Kobayashi and subordinate Mikimoto corner her. They restrain her with ropes and duct tape, then cut apart her swimsuit with a knife. Witnesses Mika Ito and Ito's boyfriend arrive; Ito removes the gag and comments on Nonogusa's body before Mikimoto forces her into oral sex with the boyfriend, who takes her virginity. This escalates into a group assault where Nonogusa eventually stops resisting. Afterward, in the nurse's office, nurse Reika Kitami confronts her about the lost virginity and repeatedly rapes her while scolding her. In the visual novel's branching paths, her interactions with Minase diverge: - If Minase exploits her vulnerability after the assault, he offers to retrieve compromising photos in exchange for sex. Despairing, Nonogusa agrees. After sex, Minase returns some photos but may withhold others. Later, under Kitami's influence, she confronts Minase about the missing photos in the locker room, sodomizes him with a double-headed vibrator, injects an aphrodisiac, and participates in his sexual torment until he dies from exhaustion. - If Minase helps without demands, he retrieves all photos and warns off Kobayashi and Mikimoto. Grateful and tearful, Nonogusa later rescues Minase from an assault by Kobayashi and Mikimoto, knocking them unconscious with a kickboard. She helps him dress, expresses embarrassment at seeing him naked, and vows secrecy. - In another path, Minase coerces Nonogusa, Kobayashi, and Mikimoto into an art-room orgy by threatening photo leaks. After violating Kobayashi, he cuts Nonogusa's swimsuit and rapes her, demanding gratitude for not letting another violate her. She experiences pleasure but begs him not to ejaculate inside her. In the OVA *Bible Black: Only* Volume 1, Kobayashi and Mikimoto abuse her again in the locker room, joined by Ito and her boyfriend in a group encounter. A separate scene shows an unconfirmed brown-haired swimmer resembling Nonogusa with Kaori Saeki in the school pool. Throughout, Nonogusa's personality remains delicate and submissive, making her a recurring target. This submissiveness manifests as initial resistance during assaults, followed by physical capitulation and occasional psychological surrender.