U. S. Marshal "Lash" La Rue and his deputy, Fuzzy Jones, head for Star City, where a gang of bandits led by the mysterious masked man, El Sombre, are ruling the town and territory. "Lash" be comes suspicious when he sees the sheriff in the saloon where he knows the gang-members hang out. Later, "Lash" discovers that Vicki, niece of the man who sent for "Lash" and was murdered, and "Piute," Indian foreman of the Burleigh property are also working on solving the many mysteries of Star City.