Hosoda, the homeroom teacher, is a perverted S man with a desire for bondage, and masturbates with a delusion of tying up his student Himesaki every night. One day, he called her to his home under the guise of career guidance, and when he dared to place a rope in a conspicuous place, she glanced at it. Seeing her, Hosoda is convinced that she has a 'bondage desire' and skillfully guides her to bondage. - She hates it at first, but on the other hand, her gets wet. From there, through Hosoda's 'punishment', her metamorphosis accelerates even further.