After making it back to the City of Dogs, Panthro is wondering why the Book of Omens is pointing to the sky. Lion-O runs into Jorma who had survived the attack on Thundera and has made it home. Upon studying the book, Jorma concludes that one of the stones the ThunderCats are after is somewhere in the sky. While exploring a secret scrap pile where new scrap metal falls from the sky, Lion-O, Tygra, Panthro, and Jorma are attacked by Necromech robots which end up stealing the Book of Omens. Upon tracking the Necromech robots, Lion-O, Tygra, and Panthro discover that they work for the Soul Sever (an alien turned robot by the Necromechs) who plans to use the power of the Book of Omens in order to find vessels for the three spirits of his deceased family.