The Valley of Vanishing Men

Wild Bill Tolliver and Missouri Benson ride into the territory of New Mexico to search for Bill's father, Henry Tolliver, who disappeared while prospecting. They discover that a ruthless outlaw leader, Jonathan Kincaid, has joined forces with Carl Engler, a renegade European general, and Kincaid owns a giant gold mine and uses captured Mexican patriots, and others, to work as slaves on his property.