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,...show more