On July 27th, university student Aoi Hinata (Miwa) has an accident. When she wakes up, Aoi Hinata finds herself in a classroom from one week before the accident. At that time, her childhood friend Riku Hasegawa (Kentaro Sakaguchi) tells her “I will tell you a secret. I can turn back time.” Aoi Hinata and Riku Hasegawa like each other, but never expressed their feelings. They share their feelings for each other and go back to one year earlier. They spend their time happily as girlfriend and boyfriend, but there is a big secret behind the time slip. In addition, July 27 is approaching.

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.