Whiplash arrives at the Royal Palace, badly wounded, and asking for help. Skeletor has tried to summon up Sh'Gora, a dreaded creature from another dimension, only to have the being turn on him and imprison him along with Evil Lyn and Trap Jaw. Reluctantly, He-Man and his allies must rescue Skeletor and join forces to stop Sh'Gora taking over Eternia and the powers of Castle Grayskull...