Résumé: With the Sword of Omens broken, and bitter division spreading over what to do with Calica, the ThunderCats are in turmoil - and the time is ripe for Mumm-Ra to strike! Casting aside his diminished appearance, the devil-priest attacks with his legion of mummified Mu'Tants. It's the moment of truth for Lion-O - will he prove himself to be a worthy leader? Or will his youth and inexperience condemn the last survivors of Thundera to their final doom?