Reiko Kobayakawa was raised from childhood on her mother's teachings to "always be kind to others," and her kindness had grown so deep that no one could surpass her in gentleness. However, this very kindness became her sole weakness. Though others often said she was too kind, that kindness eventually became exploited—by two male teachers she had a strained relationship with, Inoue and Shida. Though they usually avoided each other, the two men discovered a shared secret: both harbored a strong preference for anal. Spotting Reiko's gentle nature as the perfect opportunity, they set their sights on her, drawing her into their seductive trap.