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