A cowboy G-man joins an outlaw gang out to rob a gold shipment.

A feature film. Tarzan, who has returned to Africa after living in England, sets off to Guatemala in search of an old friend who may have survived a plane crash there. Also in Guatemala are Ula Vale and Major Martling who are out to find the riches of the Green Goddess. They join forces after they learn that a competitor, Raglan, has already set out ahead of them. Tarzan has to rescue everyone after they are taken prisoner. When they get to the hidden city, Tarzan finds his friend alive and the fabulous treasure.

A serial in 12 chapters. Tarzan goes to Guatemala to find his lost friend, D'Arnot. On the way he helps Major Matling search Mayan ruins for hidden jewels and an idol containing the formula for a powerful explosive. D'Arnot and the idol are rescued, but the idol falls into the clutches of the explorer Raglan.