Hibari, a high school student, is in a relationship with her biology teacher, Aoi-sensei. However, their love must remain hidden as relationships between teachers and students are prohibited. They are not allowed to exchange messages, call each other or go on dates, even kissing is forbidden. If any rumor spreads, they must end their relationship. Therefore, they must safeguard their love. But, Hibari noticed that Aoi-sensei seems to be blushing. This is the start of an intense and chaste love affair with her dedicated biology teacher, which makes her heart beat faster every day.
