The Feathered Serpent (William Beaudine, 1948)

In order to learn the location of a fabled Aztec treasure, a professor kidnaps his colleague, the only man able to read the ancient Aztec script that is supposed to reveal the location of the treasure. Charlie Chan and his #1 and #2 sons journey to the jungles of Mexico to find the victim and bring the kidnapper and his gang to justice.