In the aftermath of his first battle with the Mu'Tants, Lion-O attempts to use the Sight Beyond Sight to ask for guidance from their lost leader, Jaga. The vision he receives instead leads the ThunderCats to discover another Thundarian survivor on Third Earth! Meanwhile, Slithe and his Mu'Tant band have discovered the pyramid of Mumm Ra - and they're about to learn firsthand how dangerous the Ever-Living one can be!