The film is adapted from a true story. A group of troubled teenagers who are undergoing reform in a juvenile detention center are constantly in conflict. The two factions headed by Lei Gong (played by Lin Zhexi) and Gao Shao (played by Ji Yankai) are often at loggerheads, which gives Section Chief Wang (played by Lian Kai) a headache. Until the new dean (played by Xiao Qiang) arrives, she hopes to use classical music to educate this group of troubled teenagers, and specially hires the daughter (played by Cheng Yuanyuan) of the band leader (played by Jin Shijie) as a music teacher. So this group of "bad boys" began to put down their weapons and pick up their instruments in the band life, until the eve of a competition...