Naho Takamiya is a 2nd year high school student. During the spring, Naho Takamiya receives a letter sent by herself from 10 years in the future. In the letter, she liked transfer student Kakeru Naruse. Kakeru Naruse carried emotional scars from his mother's suicide and he died one year later. 26-years-old Naho Takamiya thinks about Kakeru Naruse often. 2nd year high school student Naho Takamiya, with the knowledge of what she feels 10 years in the future, takes action to change her future.

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.

The movie begins in the year 1995 where there were 5 peculiar murder cases. The murderer would always get someone close to the victim to witness how he would strangle the victim from behind with a rope but he would let the witnesses go and speak to the media on how the murders happened. Ito plays the role of Makimura, the police detective who was in charge of investigating the serial murders but failed to catch the cunning murderer and his respected superior ended up being killed as well. 22 years later in 2017 when the case is nearing its statute of limitations, a man named Sonezaki claims to be the culprit for the 1995 murders and even publishes a book titled "Watashi ga satsujinhan desu" to talk about the cases. Despite the disgust towards Sonezaki's actions, the intensive attention showered on him via the media and SNS makes him become the talk of town.