The evil wizard Kublai seeks the Golden Scepter of the Yantzee (the only item which can strip him of his magic) and terrorizes the villagers of San Francisco's Chinatown in the process. When Thundarr thwarts his initial attempts, the wizard recruits another barbarian named Zogar to engage him in battle while Kublai tries again to find the scepter.
The evil wizard Crom threatens a tribe of humans at the Alamo. They can protect themselves by using a sophisticated Guardian machine that utilizes flying robot drones that can disable the wizard's laser tanks. However, it blows a circuit and cannot be replaced as circuits are no longer produced. Their only hope is to infiltrate Crom's lair in order to use his moon dial, which sends them to Old Earth. In the 20th century, Thundarr, Ookla and Ariel are aided by a little girl named Samantha, who helps them obtain a fresh circuit. The trio return to New Earth and prepare for battle with Crom, but are glad they had a chance to see the preapocalyptic world.
After saving a old man named Tyron from the rat-like Groundlings, Thundarr, Ariel and Ookla learns that the Groundlings are in search of The Black Pearl, which the evil wizard Gemini fears it's power. Thundarr, Ariel and Ookla agrees to deliver the Black Pearl to the village of Manhat (the ruins of Manhattan). But Ariel is captured and taken to Gemini's tower and Gemini demands that Thundarr and Ookla gives him the Black Pearl or Ariel will die.