In the early 1970s, Beijing was busy with "making revolution" and adults had no time to pay attention to children. In addition, there was nothing to do when schools were closed. The young people, represented by the boys in the military compound, found their own fun and squandered their excessive hormones by making trouble, fighting, making trouble, and slapping women. Ma Xiaojun (played by Xia Yu) is such a teenager. One of his hobbies is to use a master key to open the lock of other people's homes when no one is there, and sneak in to play. It was in this way that the photo of the girl Milan (played by Ning Jing) entered Ma Xiaojun's eyes before the person. Through Liu Yiku (played by Geng Le), the "boss" of the courtyard, Ma Xiaojun saw Milan again, who had accidentally glimpsed him in the artillery bureau before, and began to formally regard him as his dream lover. However, in Milan's eyes, Ma Xiaojun was just a fur boy, and the person she liked was the mature, steady and handsome Liu Yiku. Since then, Ma Xiaojun has ushered in a mixed adolescence. This film is adapted from Wang Shuo's short story "Animal Fierceness". Xia Yu won the Best Actor (Silver Lion Award) at the 51st Venice International Film Festival for this film.