Lion-O is haunted by the recurring nightmares of Thunderians being killed on Thundera while he fled to the safety of Third Earth with Jaga and the other ThunderCats. Jaga later tells Lion-O that 3 more Thundercats have, in fact, survived and are also living on Third Earth. The ThunderCats decide to search for the 3 new Thunderians, but Mumm-Ra has plans as well and takes the new Thunderians as his prisoners to Fire Rock Mountain. Lion-O loses the Sword of Omens in an avalanche while Panthro battles the Fist-Pounder with the ThunderTank as the ThunderCats close in on rescuing the Thunderians from Fire Rock Mountain, but they'll need supernatural help if they are to pass through the Thundranium gasses to reach them.
A soldier from Earth crashlands on an alien world after sustaining battle damage. Eventually he encounters another survivor, but from the enemy species he was fighting; they band together to survive on this hostile world.
A young teenager named Mikey Walsh finds an old treasure map in his father's attic. Hoping to save their homes from demolition, Mikey and his friends Data Wang, Chunk Cohen, and Mouth Devereaux run off on a big quest to find the secret stash of Pirate One-Eyed Willie.
Captain Etienne Navarre is a man on whose shoulders lies a cruel curse. Punished for loving each other, Navarre must become a wolf by night whilst his lover, Lady Isabeau, takes the form of a hawk by day.
Taran is an assistant pigkeeper with boyish dreams of becoming a great warrior. However, he has to put the daydreaming aside when his charge, an oracular pig named Hen Wen, is kidnapped by an evil lord known as the Horned King.
As graduation nears for the class of 1955 at Angel Beach High, the gang once again faces off against their old enemy, Porky, who wants them to throw the school's championship basketball game since he has bet on the opposing team.