Her teacher, Hosoda, is a perverted sadist with a bondage fetish, and every night he masturbates to the fantasy of tying up his student Himesaki. One day, he invites her over to his house under the pretext of career guidance, and deliberately places a rope in a conspicuous place, which she glances at. Seeing this, Hosoda is convinced that she has a bondage fetish, and skillfully leads her to bondage. At first she is reluctant, but on the other hand her pussy becomes soaking wet. From there, through Hosoda's punishment, her perversion accelerates even further.