Fleeing the destruction of their home planet, Thundera, Lion-O and the ThunderCats land on the mysterious, dangerous all-around awesome world of Third Earth! But their enemies, the Mutants of Plun-Darr, have followed them and it turns out Third Earth already has a Mumm-Ra problem. Can Lion-O learn the ropes of being a leader in time?

The ThunderCats land on the mysterious world of Third Earth!

The ThunderCats land on the mysterious world of Third Earth!

Lion-O has gotten a hold of the last jar of Thundersnaps!

Lion-O wants to prove he’s not just some boring old adult.

Panthro is getting fed up with having to fix things.

A crying unicorn appears at the Cats' Lair.

Vultureman has got a brand new invention.

Third Earth is being overrun by Warrior Maidens.

Lion-O needs to plug the Sword of Omens into the Cats' Lair.

Tygra teaches Lion-O about trust.

Tygra's feeling unappreciated by the other ThunderCats.

Monkian beats Cheetara in a race?!

Lion-O releases a space prison-full of space criminals.

Lion-O is tasked with mapping the beaches of Third Earth.

Lion-O accidentally opens a portal to the Astral Plane!

Mumm-Ra can get swole whenever he wants!

The Cats' Lair is attacked by gold-loving robot pirates!

The ghost of the ThunderCats mentor is now free.

Panthro hits it off with a new friend!

After a battle with the Mutants, Jackalman gets confused.

The ThunderCats are exhausted from fighting bad guys.

Cheetara is caught in a trap set by Safari Joe.

The Mutants’ old leader Ratar-O arrives.

Lion-O is accidentally stomping on a miniature village.

Lion-O and the other ThunderCats meet a new Thunderian!

Snarf leaves the Cats' Lair to get a needed vacation.

Mumm-Ra and the Mutants team up.

The Mutants and Mumm-Ra control the Cats' Lair!

The Cheetara Corp employee retreat gets cancelled.

Lion-O meets Hachiman, a cool Samurai warrior.

Tygra creates a bunch of new laws for Third Earth.

A crate with fifty Swords of Omen lands on Third Earth.

The ThunderKittens plug a new video game into Snarf.

The ThunderCats tell the Berbils to stand up for themselves.

Santa Claus is on the run from Mandora!

Mumm-Ra plans to disguise himself as a Thunderian.

A local sword shop sells an ultra powerful sword to Ratar-O.

Lion-O's dad arrives on Third Earth and he's a big jerk!

Cheetara tries to save the Berbils.

The ThunderCats eat the last of the Thunderian food.

Mumm-Ra builds a mall to trap the ThunderCats forever.

Third Earth's sun is being blocked out by the a corporation.

The ThunderCats freak out by a spooky ghost.

The ThunderCats agree to foster a demonic puppy.

The ThunderKittens unleash a demon who is powered by fear.

The ThunderCats invite a swamp man into the Cat's Lair.

The rulers of Plun-Darr will bring one of the Mutants home.

The Mutants refuse to celebrate their favourite holiday.

Mumm-Ra decides he'll nap for a thousand years.

The ThunderCats face the greatest threat of their lives.