College student An Mashiro is attacked by a thug on her way home from school. By chance, Shota and Kenji happen to be nearby and together they fend off the attacker, but Kenji gets injured in the process. Grateful yet guilty, An invites them to her place to treat his wounds. However, that's when the real story begins. Before she realizes it, An becomes the target of the boys' escalating pranks. Forced to change into a swimsuit, she's subjected to double fellatio, has her bath invaded, and is penetrated by their young penises—completely overpowered and stripped of her autonomy. Gradually, she loses all ability to resist, ultimately falling entirely under their control. What starts as mere mischief evolves into a deeply disturbing incident that profoundly alters their relationships, culminating in a shocking conclusion that will leave viewers stunned.