Uchiyama Kaede and Shiina Kasumi, were best friends. Now in high school, Kasumi became more popular than Kaede, which led her to continually intimidate her former best friend. One day after school, Kaede finds Kishida Takumi, a bicycle thief who is especially talented at unlocking locks. She asks him a favor, if he could open the door to the roof of the school. Meanwhile, the arrival of a new teacher will bring changes to school.