Gojo Koi is assigned to replace a teacher on leave. - She was aiming to become an enthusiastic teacher, but the female teacher had the only mistake that even her fiance didn't know about. - One day, he tries to seriously face his students, but one student discovers that he has had a past mistake. - The students who grabbed the past were merciless... - Her J-cup megaton breasts are tied up and she is confined to her movements. - The more she struggles, the harder the hemp rope digs into her clusters, and the more she screams, the more she sneers, the more she sneers. - With her freedom taken away, her bulge is roughly massaged, sucked on both sides, and repeatedly reaches unwanted orgasms, and ends up being rigged. - As she is humiliated, her breasts become unnoticedly more sensitive... - A female teacher who has worked hard to face education, unable to resist, falls into sexual toys for her students...