The Small California tow of Diablo is plagued with mysterious deaths after Sheriff Robert Lopez unearths an ancient box. Legend has it that the box holds the sixteenth-century Mexican demon named Azar. FBI agent Gil Vega is sent to investigate the murders and joins forces with the Sheriff's daughters. Dominique and Mary. Together the trio descend into a noghtmare world of supernatural terror in which they are pitted against the bloodthirsty Azar and forced to defend their lives with the only weapon they have left.