El Puma, a Mexican desert guide, escorts an archaeological expedition headed by Professor Lucius Lloyd through the Indian badlands of Mexico. Marian, the professor's niece accompanies the party as only she can translate the Aztec writings in the diary of her father, murdered on a similar expedition six years previous. The professor is murdered by a knife, and the weapon is recognized as the property of El Puma. Magpie, a Federal Investigator, knows that El Puma is really "Lightnin' Bill' Carson, a former federal agent who has been missing since Marian's father was slain. The reluctant Magpie believes that his old pal is guilty. Carson sets out to prove otherwise.
Tim McCoy
Joyce Bryant
Ben Corbett
Ted Adams
Budd Buster
Dave O'Brien
Forrest Taylor
Reed Howes
John Elliott
Kenne Duncan
Herman Hack
Chick Hannan
Carl Mathews
Lew Meehan
Kansas Moehring
Artie Ortego
Tex Palmer
Tom Smith
Frank Wayne
Wally West
Dan White