An ancient temple is found within Mount Eternia, and when investigating it, Orko accidentally unleashes The Energy Beast, a powerful electrical demon that once ruled Eternia. He-Man, Man-At-Arms and Teela must drill into the mountain to find the Gold Chamber, which contains the magic needed to control the Energy Beast, before it is too late. But they also face trouble from Skeletor, who is hoping to strike a deal with the Energy Beast himself.