
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
Bill Carson posing as El Puma

Joyce Bryant
Marian Willis

Ben Corbett
Magpie

Ted Adams
Link Benson

Budd Buster
Old Dobie

Dave O'Brien
Dr. Jerry Leonard

Forrest Taylor
Prof. Lucius Lloyd
Reed Howes
Sheriff

John Elliott
Prospector

Kenne Duncan
Henchman

Herman Hack
Henchman
Chick Hannan
Henchman

The Man from Thunder River
The Man from Thunder River

The Settlers
The Settlers

Under the Tonto Rim
Under the Tonto Rim

The Whispering Skull
The Whispering Skull

Silver Lode
Silver Lode

5 Card Stud
5 Card Stud

Shanghai Knights
Shanghai Knights

Bad Day at Black Rock
Bad Day at Black Rock

The Salvation
The Salvation

Under California Stars
Under California Stars

The Lone Rider Rides On
The Lone Rider Rides On

Sundown Riders
Sundown Riders