Mayumi is a teacher for a class of students, and one of them is a girl named Ajima, who frequently visits her boarding house. It seems that Ajima is being bullied due to her complicated family background. Mayumi actively tries to communicate with her to provide support, but all her efforts end in failure. Struggling with her own lack of confidence stemming from her inadequacies as a teacher and the trauma of losing both her best friend and her lover, Mayumi finds encouragement in the casual words of Rin. In the midst of this, Mayumi receives a summons from the school, which appears to be related to inappropriate conduct involving Ajima and her half-sister, Sakura.