From beyond any known galaxy, bring with them the laws and ideals of their doomed planet, Thundera, come the ThunderCats.

The Mutants form an unholy alliance with Mumm-Ra and set forth to destroy the ThunderCats.

The ThunderCats meets the Berbils, a group of robot teddy bear-like creatures from the planet Ro-Bear.

The ThunderTank is given a trial run as the ThunderCats attempts to liberate the Brutemen from slavery.

Mumm-Ra changes into a puma and stages a fake heroic deed in order to convince the ThunderCats that he's from their home planet.

The Code Of Thundera is called into action as Lion-O saves a unicorn from the Berserkers and their leader, Hammerhead.