Erin McKenna, a beautiful songwriter married to a crooked Los Angeles County sheriff’s deputy, is kidnapped by Benjamin Armenta, the ruthless leader of the powerful Gulf Cartel. But his demands are as unusual as the crumbling castle in which Erin is kept. She is ordered to compose a unique narcocorrido, a folk ballad that records the exploits of the drug dealers, gunrunners, and outlaws who have populated Mexican history for generations. Under the threat of death, Armenta orders Erin to tell his life story in music and write “the greatest narcocorrido of all time.”