He-Man and the Masters of the Universe team up with the ThunderCats—the epic crossover event you’ve waited thirty years to see! In his ever-living desire to destroy the mighty ThunderCats, Mumm-Ra quests for a weapon that can rival the legendary Sword of Omens: He-Man’s Sword of Power! But his dimension-spanning scheme kick starts a cataclysmic crisis that will embroil heroes and villains—Masters, Mutants and ThunderCats—in a mind-blowing six-part saga!
List of covers and their creators:
|A||Cover A (Heroes)||Freddie E. Williams II||1|
|B||Cover B (Villains)||Freddie E. Williams II||3|
|Var||Adult Coloring Book Variant Cover||Freddie E. Williams II||4-6|
|2nd||Second Printing Cover||Freddie E. Williams II||2|
On Third Earth, Lion-O and the Thundercats defeat Mumm-Ra yet again, forcing him to return to Onyx Pyramid, where the Spirits of Evil, give him his next mission, to collect the Sword of Power.
On Eternia, Prince Adam is late for a ceremony by his father, King Randor, to honor Adam. Adam makes a fool of himself in front of the Masters and his parents, who don't know that Adam is really He-Man. This causes Randor to scold his son, but is interrupted when Third Earth breaks into Eternia's reality and space.
This causes earthquakes across both Eternia and Thrid Earth. The Thundercats know something is up when Jaga appears to warn them that Mumm-Ra has done something very evil. Meanwhile on Eternia, Adam saves King Randor, and then is approached the Sorceress. She warns him great evil is near and to give her the Sword of Power. She then stabs Adam through the chest and reveals to be Mumm-Ra.
Adam is able to change into He-man and fight Mumm-Ra, but the evil wizard escapes with the Sword. Mumm-Ra returns to the Onyx Pyramid where he is betrayed by the Spirits of Evil. They destroy him and give the Sword of Power to Skeletor.