Fourty-eight-year-old salaryman Hiroshi Nakahara accidentally takes the wrong train to Tokyo after a business trip in Kyoto. He decides to accept his situation and sit back when he learns that the train is headed toward his hometown in Kurayoshi.

As he walks the streets of his childhood neighborhood, Hiroshi realizes how significantly the place has changed in the 20 years since his mother died. While visiting her grave in the Genzen Temple, he is transported back into the body of his 14-year-old self. Retaining the memories and wisdom of his middle-aged mind, he is now an eighth grader in junior high school.

Hiroshi's regained youth enables him to escape the reality of being an adult man with a wife and two daughters. Unaware how to return to his original time, he begins to relive his adolescence. During his time travel, Hiroshi attempts to uncover the reasons for his father's abandonment of the family in hopes of understanding him and his actions.