孤僻的青年村崎十三(小栗旬 饰)少年时代饱受同班同学赤井欺侮,在极度的痛苦与憎恨之中,他的体内逐渐分裂出另一个残暴无情的人格——13号(中村狮童 饰)。 村崎辗转搬到了赤井(新井浩文 饰)所在的公寓,与之为邻,并在赤井所在的建筑队工作。当过暴走族的赤井如今有了一个幸福的小家,不过暴躁的性格从不曾改变。他早已忘记了当年的受气包村崎,在工地中依然对他百般欺负。不断的刺激和痛苦的回忆,令恐怖的13号渐渐苏醒,继而展开对仇人及其家人的疯狂报复……Jûzô Murasaki is a boy miscast in his classroom, being frequently abused, tortured, beaten and humiliated by the bully Tôru Akai and his gang of juvenile punks. After years of repression, rejection and fear without facing Akai, he develops a psychopathic dual personality with a violent alter-ego. While living in the apartment 13 of a tenement building, he becomes unable to control his violent dark personality, who plots an evil revenge against his upper floor neighbor Akai and his family.