Tennoji Karen is an aspiring idol. Too busy with schoolwork and lessons to sleep, Utakoi often dozes off in an empty classroom, where she met Yuto. As he secretly interacts with Karen, who is gaining attention within the school as a future idol, he gradually deepens his friendship with her. One day, when Karen says she does not sleep well and is tired, he gives her XXX suggestion to help her sleep efficiently. After a short but very good night's sleep, Karen, who was not tired for the first time in a long time, seemed impressed. After repeating this several times, his mischievous spirit is uncontrollable and he plays a prank on the sleeping Karen. Eventually, this escalated and a line was crossed. As he continues his relationship with Karen, Mikoshiba Saria, who is in the same grade as her and belongs to the same office, finds out about it. She is a model and sees Karen as a rival. She tries to find out what she's doing to see if it can be used to take Karen down. Yuto, who had heard it out using xxx suggestion, decided to punish her with moxibustion as a way to encourage him to reflect on his behavior. Contrary to Karen, he makes her believe that Saria secretly has a lover and that Yuto has found out about it, and he does his bidding to keep the secret.

While enjoying his secret relationship with the serious and honest Karen, Yuto finds pleasure in bringing the winning personality of Saria to her knees.