Thundarr the Barbarian

After Thundarr defeats him, the evil wizard Sarott plots a return to power with the help of the miniaturized City of Thieves: If he restores the city to normal size, its evil citizens will help Sarott defeat all humans and reign supreme. But first, Sarott must seize the Gauntlet of Power to strengthen his magic enough to restore the City of Thieves.