Montoya Santana (Edward James Olmos) is a young Chicano living in East Los Angeles when he and his friends form a gang. J.D. (William Forsythe) and Mundo (Pepe Serna) have pledged to stick with him, but soon all three juveniles are arrested for a burglary. Santana doesn't learn from his experiences in the juvenile justice system and he ultimately finds himself in prison facing a long sentence. The brutality of his surroundings is little different than that on the streets. He soon becomes leader of a powerful gang faction in prison that also has control of illicit businesses outside the walls.