Kosu x Kosu is a oneshot about Isumi Seiji, a high school art student who frequently coaxes female students into becoming his models, and Takamiya Ayase, the student council president who always reprimands him.

After repeatedly refusing to become Seiji’s model, Ayase decides that the only way to stop him is to disband the art club. As she attempts to do so, however, she is cursed by a third party, and the only one who can free her from the curse is none other than Seiji.