Border Patrol agent Grant Newburg works undercover to infiltrate a gang of outlaws who are smuggling illegal Chinese immigrants into the United States by way of the Grand Canyon. During his investigation, Newburg stumbles across a dazed young woman - Estelle Halloway - wandering lost in the canyon, apparently separated from her companions. Newburg rescues Estelle and vows to protect her, unaware that her companions were the very group of smugglers that he has been working to arrest. (texto oficial de la distribuidora)