A young woman visiting in Mexico is kidnapped by a gang of bandits, who drag her through the rugged wilderness to their hideout. She manages to leave word for her friend Bill, who knows the country well. But when Bill cannot find a horse, his only available form of transportation is his roadster. Nevertheless, he is determined to come to her rescue, even though it means trying to drive the car across miles of rocky, broken terrain.

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.