When an archaeologist (John Van Pelt) disappears while hunting for the lost city of Lukachukai, his daughter turns to the Three Mesquiteers -- Stony (Bob Livingston), Lullaby (Max Terhune) and Tucson (Ray Corrigan) -- for help. Their search uncovers even greater mysteries, and as they encounter a tribe under the control of a power-mad white man, members of the search team vanish, and it becomes apparent that there's a traitor among them.