El Mariachi just wants to play his guitar and carry on the family tradition. Unfortunately, the town he tries to find work in has another visitor, a killer who carries his guns in a guitar case. The drug lord and his henchmen mistake el Mariachi for the killer, Azul, and chase him around town trying to kill him and get his guitar case.

The killing of a political leader shatters the peace of a small Mexican town. MANCO, the brother of the murdered presidential candidate knows the killer and sets out to exact his revenge. Arriving to investigate the assassination is special agent AMIGO from the Mexican Intelligence. Amigo quickly strikes up a friendship with a local hotel owner who fills him in on the town's seedy characters and gives Amigo a Single Action revolver. The stage is set for Amigo and Manco to join forces and take down the powerful and dangerous CAMARO family responsible for the murder and the corruption of the town. To gain the confidence of Camaro, Amigo breaks his top henchman out of jail. Amigo is welcomed into the Camaro gang. Camaro soon discovers Amigo's connection with Manco and plots to take him out. The situation reaches a boiling point on the US/Mexican border when Amigo, Manco, and Camaro meet for an old-fashioned Western shootout where truth and justice prevail in one single action.