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
as Bill Carson posing as El Puma
Joyce Bryant
as Marian Willis
Ben Corbett
as Magpie
Ted Adams
as Link Benson
Budd Buster
as Old Dobie
Dave O'Brien
as Dr. Jerry Leonard
Forrest Taylor
as Prof. Lucius Lloyd
Reed Howes
as Sheriff
John Elliott
as Prospector
Kenne Duncan
as Henchman
Herman Hack
as Henchman
Chick Hannan
as Henchman
