Adapted from the manga Hell Dogs by Fukamachi Akio.

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.

Gouda Takeo is a big guy with a heart just as big. Unfortunately, the girls are not interested in him and only want his good-looking best friend, Sunakawa. Accepting the fact, Takeo is content with his single life. However, one day, after saving a girl named Yamato from a harasser, he unexpectedly turns his life around.