is a Japanese manga series written and illustrated by Mitsurō Kubo.

[2] It was serialized in 2011 in Weekly Shōnen Magazine published by Kodansha until reaching its conclusion in 2014.

It was adapted into a Japanese television drama series in the summer of 2014.

[3] Kin'ichirō Imamura, a high school senior, prepares to graduate with no friends and having never participated in extracurricular activities.

An accident on the last day of school somehow sends Imamura and Akira Fujieda, a popular girl in Imamura's graduating class, back in time to their first day of high school.