He-Man/ThunderCats defeated villains and Cringer runs into He-Man's arms thrilled his best friend is alive. The three rush back to the ship desperate to get back to Eternia before it is too late. The four Ancient Spirits of Evil have arrived on the doorstep of Castle Grayskull while Skeletor and Mumm-Ra look on. Randor has assembled an army alongside the Thundercats and the combined heroes attack the giants. Man-At-Arms, Tygra, and Panthro assemble a cannon of combined Eternian and Thundarian tech to attack the Spirits while the others buy them time. Inside the Castle the Sorceress summons the Castle's defenses to
He-Man/ThunderCats Sorceress, who managed to get free while they traveled realities, summon the recovered heroes to support Lion-O and He-Man. Mummator starts to unlock the orb and the Power of Grayskull begins to flow into him. Even He-Man begins to weaken as his power is taken. Lion-O manages to slash Mummator's wrist and get the Power Sword back but it is too late to stop the orb from unlocking. Realizing they have one last chance He-Man and Lion-O risk combining the remaining power of Grayskull in He-Man and the Power Sword with the Sword of Omens even though both realized it