Elementary school student Naoki Kikuchi killed his step dad because he beat him everyday. His best friend Ryo Makino never thought Naoki did anything like that. Ninomae police caught Naoki and the court gave him 5 years reformatory. He continued his study from there and after being released from the reformatory he was admitted to a high school in Ninomae. In his first year of high school, he met with his elementary school's best friend Ryo and met some new people. But because of the past incident he always tries to hide himself from others. I'm not my past tells the tale of Naoki & his honest attempts to redeem himself, all while being continually haunted by the shadows of his past.