While accompanying Professor Naska and his students on a field trip to Ancient Aztek ruins in Mexico, El Dorado is attacked by Alien Invaders. When El Dorado scares them off, an angered Alien Mummy attacks El Dorado and the others. Meanwhile at the Hall of Justice, Superman and Wonder Woman receive a U.F.O. alert and head out to Mexico. When the two Super Friends arrive see The Alien Mummy has El Dorado and the others have been put under mind control. When Superman and Wonder Woman confront the Alien Mummy, he turns both of them into golden statues. Wonder Woman's attempt to communicate telepathically with El Dorado was a success when he breaks free of the Alien Mummy's mind control and distracts the Alien Mummy with a hologram Beast. Meanwhile he transports himself to find his Super Friends turned to gold. El Dorado brings them back to the Alien Mummy who gets his power source broken by Superman's X-Ray vision which returns everyone to normal. El Dorado leads the Alien Mummy into his spacecraft and Superman sends him off.
