In Los Angeles, the street gangs unite and declare war to the police. Meanwhile, a father stops his car in a suburb and his daughter goes to an ice-cream truck to buy a ice-cream. She is murdered in cold blood by a member of one gang. The father follows the guy, kills him with many shots and runs to the Precinct 13. The policeman Bishop has just assumed the police station, which is not in operation but waiting to be closed on the next morning. With him, there are two women: the telephone operator and Leigh. A few moments before the arrival of the shocked father, a bus transporting three prisoners had stopped there and the escort policemen requested cells to lock the prisoners while waiting for a doctor for one of them that is ill. Suddenly the precinct is under siege and violent attack of street gangs.