In the show, the space barbarian family Zandor, Tara and son Dorno fight alongside their giant pets the Herculoids — laser dragon Zok, space rhinoceros Tundro, rock ape Igoo and the shape-shifting Gloop and his son Gleep — to keep their planet safe from invading robots, mad scientists and mutants. The diverse team fought an endless battle against a stream of villains including, according to "Children's Television: The First Thirty-Five Years", "the Faceless People, Destroyer Ants, Raider Apes, Mutoids, Arnoids, Zorbots, the Mekkano mechanical men and the Ogs, a strange form of vegetable life."