Ayuha Samaru (Minami Hamabe) is a high school student. She is honest and works hard at everything, no matter what. One day, she has trouble at a gyudon restaurant due to money. A man at the restaurant, Yoshitaka Hiromitsu (Ryoma Takeuchi), helps her out. The next day, she finds that Yoshitaka Hiromitsu has come to her school as a substitute teacher for her ill homeroom teacher. Ayuha Samaru now believes that Yoshitaka Hiromitsu is her fate in love. She keeps expressing her feelings to him. --asianwiki

I (Takumi Kitamura) am a high school student. I happen to find a diary by my classmate Sakura Yamauchi (Minami Hamabe) that reveals she is suffering from a pancreatic disease. I spent time with Sakura, but she dies. 12 years later, due to Sakura’s words, I (Shun Oguri) am now a high school teacher at the same school where I graduated from. While I talk with my student, I remember several months I spent with Sakura. Meanwhile, Kyoko (Keiko Kitagawa), who was Sakura’s friend, is soon to marry. Kyoko also recalls the days she spent with me and Sakura.