 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.