With their home planet, Thundera, about to explode, the Thunderians flee to a distant galaxy. Before they can make the long journey the Mutants sweep in and destroy most of the fleet in an attempt to …

The Mutants, who have also reached Third Earth, encounter an old pyramid. It turns out to be the home of Mumm-Ra the Ever-Living, and they join forces to capture the Sword of Omens. Both the Mutants a…

The Ro-Bear Berbils are a friendly group of robot bears that live on Third Earth. Lion-O and Snarf don't know this, and end up getting caught in a Ro-Bear trap. The Berbils free them however, and they…

The homeless Mutants also make plans to build their home. They enslave a primitive race of beings called Brute-Men to do their work for them. The Thundercats go to Castle Plunn-Darr to free the Brute-…

Mumm-Ra uses his shapeshifting abilities to pass himself off as a Thunderian so he can stage the "rescue" of Cheetara and infiltrate Cats' Lair.

When Snarf and a young unicorn are captured by the pirate Hammerhand and his crew of Berserkers, Lion-O goes to rescue them.

With their supply of Thundrillium running low, the Thundercats set off in search of a fresh supply. Tygra detects a large deposit in a cave and goes to investigate - unfortunately, he has entered the …

Wilykit and Wilykat try to stop a band of living gargoyles from robbing a Wollo but fail to do so and trail the gargoyles to a nearby Tower. Wilykat is trying force the door open when he suddenly disa…

While investigating an earthquake, Tygra stumbles across the Garden of Delights and meets a talking plant named Silky, who offers him her fruit. But it turns out that "Silky" is another of Mumm-Ra's d…

Lion-O and Snarf stumble upon a portable jail cell, and mistakenly open it up. Three of the galaxy's worst villains escape. One of them, a slick thief, manages to steal Lion-O's sword. Lion-O helps Ma…

Two Bolkins (sheep-like beings from Third Earth) unleash the ghost of Grune the Destroyer, a renegade Thundercat who once terrorised Third Earth and now turns his attention to the Thundercats.

Mumm-Ra and the Mutants plot to open the Time Warp Prison and release the evil Princess Ta-She in order to use her deadly Doomgaze against the Thundercats.

When a meteorite made of pure Thundrillium crashes on Hook Mountain, the Thundercats decide to use it to replenish their depleted energy supply. But Lion-O must first gain the trust of the fierce Snow…

Tired of constantly being bested by the Thundercats, the Mutants have Mumm-Ra raise their spaceship and salvage their vehicles.

Lion-O becomes homesick, and his memories of Thundera are almost nonexistent. Jaga appears to Lion-O and tells him that on their spaceship, they brought with them a time capsule which contained a reco…

The Mutants, once again searching for a way to destroy the Thundercats, recover some more items from their spaceship. They take their ship's engine and convert it into a giant fireball-shooting machin…

Mumm-Ra tricks Lion-O into using the Sword of Omens against Tygra, causing the blade to break in half and lose its powers. The only way Lion-O can restore the Sword is to venture into a volcano and ha…

Mumm-Ra creates device that can make Panthro clones. He embeds the spirit of Hammerhand into his clone and sets it free to destroy Third Earth. The Third Earth inhabitants blame the Thundercats for th…

Wilykit and Kat accidentally free an ancient monster that was banished to an old shrine centuries ago. The evil monster, Mongor, begins to destroy the planet, and is much stronger than the Thundercats…

The Thundercats briefly show Lion-O how the time capsule they recovered from the caveman works. Curious to see more, Lion-O activates it during his night-time watch, and gets caught in its projection …

An old scientist seeks the Thundercats to help him save the oceans of Third Earth. Long ago, a crack was made in the bottom of the ocean which caused the water to drain into the earth's core. Dr. Dome…

Jaga is captured by Nemex, an evil being in the Astral World, and Lion-O tries to find a way to rescue him. Third Earth legend says that the only person who can transport anyone to the Astral world is…

The Thundercats think that Snarf is getting too old, and that he is not up to doing as much as he does. To prove them wrong, Snarf saves the Thundercats from another mess. The evil Crystal Queen, Tart…

An evil hunter lands on third earth in search of prey to hunt. His holographic machine can tell him about all of the Thundercats, including their strengths and weaknesses, and he is able to hunt down …

Nearly all the Thundercats have been captured by the Mutants and imprisoned in Mumm-Ra's Pyramid, forcing Snarf to use his own talents to free them.

An alien spaceship crash lands on third earth, and it can somehow communicate with Cheetara through her sixth sense. She becomes a part of the spacecraft, and begins to feel what it feels. The Mutants…

Mumm-Ra summons the great samurai Hachiman to seek and destroy Lion-O. He tells Hachiman that Lion-O and the Thundercats are destroying his planet. Hachiman and Lion-O confront each other, but their …

Mumm-Ra has a phial of miniaturization gas. Vultureman builds a mechanical Wolfrat to infiltrate the gas into the Cats' Lair. The ThunderCats are immediately reduced to nine inches high. Knowing how v…

Vultureman summons Ratar-O to take him to the planet of the Snarfs to capture one of them and use it as ransom with the Thundercats. Snarf, thinking his entire race was wiped out when Thundera blew u…

The ThunderCats race to try to salvage the part they need for the Feliner from the wreck of the Rat Star before the Mutants can complete repairs. Snarf contemplates leaving the ThunderCats forever.

Mandora, on space-patrol, encounters an old pirate ship which doesn't meet inter-galactic standards. She boards the ship, arrests the pirate, and sends the ship to a space prison. Little does she kno…

The Driller, Mumm-Ra's servant who captured Panthro for him in Spitting Image, returns to aid Mumm-Ra once again. His job this time is to drill a hole from the Cats' Lair to the Acid lake, allowing th…

Wiz-Ra, Mumm-Ra's enemy from long ago, comes back every 7000 years through a portal that just happens to be in Cheetara's bedroom. Wiz-Ra wears a magical helmet that lets him control minds. When the…

Mumm-Ra finds out that the Kingdom of Webs has a new Queen, Spidera. Mumm-Ra thinks he can lure Lion-O into her lair. He transforms into a diamond fairy and casts a spell on Lion-O. Snarf follows t…

Mumm-Ra hires Captain Shiner to send a fake distress signal to the ThunderCats. With their new vehicle, the Feliner, the ThunderCats set out into deep space to help the "ship in distress". When they …

Wilykit and Kat find an ancient harp that has a genie in it. His name is Charr-Nin. Mumm-Ra appears to the genie and tells him that if he destroys the Thundercats, he will be freed from his eternal p…

On Lion-O's 20th birthday, he must pass a set of trials to become the true Lord of the ThunderCats. Even though he is the hereditary Lord of the ThunderCats, he must prove himself to be worthy of that…

A vagabond space traveler lands on Third Earth to challenge Mumm-Ra to a fight. The Demolisher is victorious against Mumm-Ra and sends him running back to his tomb. Mumm-Ra acknowledges the power of…

Monkian goes to Mumm-Ra and agrees to give him anything if Mumm-Ra will make him powerful enough to rule Third Earth. Mumm-Ra agrees, and gives him Power Spheres which make him super strong and give …

After the Mutants fail to ambush and defeat the Thundercats with Vultureman's new Thundrainium cannon, Vultureman, furious about the failed attempt and the loss of his weapon, activates a self-destruc…

Micrits, a tiny race of human-like figures, happen to live right outside Cats' Lair. Unaware of their existence, Lion-O manages to continuously step on their village and destroy their homes. Upset a…

On the second day of his trials, Lion-O must race Cheetara through the dangerous lands of Third Earth. Although Cheetara is by far the fastest among the Thundercats, her speed can only last for a shor…

Mumm-Ra awakens the Rock Giant, an ancient monster made of stone which looked like a mountain to the TCats. When it wakes up, Mumm-Ra sends it to destroy Cats Lair. The TCats try and defeat it using t…

The normally submissive JackalMan decides to start his own army in hopes of conquering Third Earth by himself. He does manage to give the Thundercats trouble, but soon he is defeated and ends up crawl…

An evil robot monster is attacking the Tuska Village, in an area unexplored by the Thundercats. Turmagar, the leader of the Tuskas, travels to the Cat's Lair to ask for aid in defeating the Techno-Ped…

Wily Kit and Kat stand in Lion-O's way on the third day of his trials. Lion-O must beat them through the maze of infinity. Attempting to stop Lion-O and slow him down, the kids set traps in the maze. …

Mumm-ra transforms himself into a ro-bear berbil (a Thundercat ally). He acts hurt and the Thundercats let him stay at Cats Lair. One night, Mumm-ra(the berbil) puts all the Thundercats under his spel…

Panthro invents flying video cameras which are suppose to record the events that take place on third-earth so they could create their own holographic time capsule. Mumm-Ra, in hope of destroying the T…

When a big storm hits Third Earth, the Thunderkittens are trapped in an old space capsule. Meanwhile, Tygra and Cheetra almost crash the Feliner, but Lion-O guides them in for a safe landing with the …

Lion-O undergoes the fourth task in his Anointment Trial.

The story of Excalibur, the greatest sword in history, is revealed to Mumm-Ra, who is then determined to find the Excalibur and defeat Lion-O and the Sword of Omens.

A giant Ice King is accidentally released from his glacial prison and attacks the Castle of the Snowmen.

A Terator Starship, an extremely ugly spaceship, is pursued by a Kymera Craft, a visually appealing spaceship. The Terator Spaceship escapes and lands at the Cats' Lair

A spaceship freighted with a lethal radioactive sphere is on a collision course for Third Earth.

Vultureman invents a voice imitator that imitates the ThunderCats' voices. He uses it to lure the ThunderCats into perilous situations.

Mumm-Ra transforms into Mumm-Ra the Dream Master and summons spectral Dream Selves from the sleeping Panthro, Cheetara, Tygra, Wilykat, and Wilykit.

Willa is practicing her long-bow skills when a warning device alerts her to a Mutant attack. Willa is captured and the ThunderCats rush to rescue her.

Mumm-Ra summons the Mutants and threatens to banish them from Third Earth unless they bring him the Sword of Omens.

Vultureman invents a Super Power Potion which give him magical powers, enabling him to mesmerize and defeat Tygra.

Jackalman ambushes Snarf and attempts to steal the Sword of Omens. This gives Panthro the idea to make a duplicate sword as bait for the Mutants.

The concluding trial in Lion-O's Anointment Trials pits him alone and weaponless against the evil Mumm-Ra.

To prove themselves worthy of being ThunderCats, the ThunderKittens borrow the other ThunderCats' weapons and practice with them. They are ambushed by Mutants, who take their weapons.

The Feliner is attacked by the RatStar, manned by the Mutants. Jackalman, Monikan, and S-S-Slithe are ejected and saved by Mumm-Rana, a female mirror image of Mumm-Ra, who is a force for good.

Vultureman invents the Shifter, a device that can switch personalities, and uses it on Panthro's personality and Snarf's body.

Mumm-Ra creates a museum where painting and statues come alive to oppose the ThunderCats.

Recurring nightmares of Thunderians killed on Thundera as he fled to safety with Jaga and the other ThunderCats awaken Lion-O. Jaga comes to tell him that they in fact survived and are living on Third…

Lion-O's rescue attempt fails and the captured Thunderians are taken to Fire Rock Mountain after another failed attempt on their part to break free from their captors.

Lion-O loses the Sword of Omens in an avalanche. Panthro battles the Fist-Pounder with the ThunderTank. The Mutants arrive at Fire Rock Mountain to take control of the prisoners.

The Thunderians attempt to escape their prison. Lion-O arrives at Fire Rock Mountain and is confronted by Hachiman who believes Lion-O is causing the suffering of his ancestor.

Lion-O and Hachiman are reconciled and 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 gase…

Mumm-Ra is weak and faces the threat of three new ThunderCats; he sends the Mutants to release his old enemies, the Lunatacs, imprisoned in Dark Side[29] in order to bolster the forces of evil. The Th…

The Mutants succeed in releasing the Lunatacs. The ThunderCats discover their Thundrylium mine is being looted and people are being kidnapped from the villages. Lion-O & the ThunderKittens have their …

The ThunderCats build the Tower of Omens to monitor for Sky Tomb, which will be run by the new ThunderCats. Disguised as a Berbil, Ma-Mutt spies on the ThunderCats' plans and the Lunatacs are sent to …

Mumm-Ra's power is restored. Snarfer makes it to Third Earth, but crashes in Dark Side. The ThunderCats rush to his aid before the Lunatacs can get a hold of him.

The ThunderCats look for Sky Tomb to free the slaves imprisoned inside it. Bengali must learn the importance of teamwork as Lion-O leaves him with guard duty. Lynx-O and Cheetara run reconnaissance to…

By disguising himself as Jaga, Mumm-Ra tricks Lion-O into believing the new ThunderCats are traitors so that they will fight amongst themselves.

Mumm-Ra tells Alluro where to find a talisman that boosts the self-confidence of the one who possesses it so that they become nearly invincible. Snarf learns that true courage comes from within.

Ma-Mutt digs up an ancient book, which leads Mumm-Ra to search for the ancient evil of the mask of Gorgon

The Lunatacs look for Thundrylium in a cave on Hook Mountain, only to be driven mad by a strange creature that turns them against each other.

Mumm-Ra coats the Bezerker's weapons and armor with Thundranium. Wilykit and Wilykat find that guarding Cats' Lair is not always a breeze.

Mumm-Ra activates a mesmerizing beacon on Ravage Island, which draws the ThunderCats to it and takes hold of their minds.

While taking care of a dangerous Suspension Capsule, dug up near Cats' Lair, Lion-O is exposed to harmful gasses inside that cause him grow younger. If the ThunderCats do not find a solution in time, …

Vultureman builds a sonic gun from a sound stone he stole in Dark Side as the Lunatacs join with him to attack the Tower of Omens.

The day of the centennial total eclipse has arrived, and any spell Mumm-Ra casts will last until the next eclipse. He declares a "Day of Decay" on the Cats' Lair, causing it to fall apart.

Chilla freezes Snarfer's spaceship as he heads back to the Tower of Omens with Berbil Mexican takeout. When Mandora gets involved, Chilla freezes her and becomes a fugitive from the law as Mandora set…

Luna discovers that her grandmother's magic belt is now in the possession of Mumm-Rana, who claimed it after battle. She heads straight for the white pyramid, with Pumyra hot on her tail.

While Hachiman is on his way to the Tower of Omens, Luna steals his sword, the ThunderCutter, and gives it to an automaton. Lion-O and the ThunderKittens head out to find their old friend.

Fed up of feeling useless, Wilykat convinces his twin to run away from home, but living on their own is more dangerous than they realized. The other ThunderCats search desperately to find them as they…

While all the ThunderCats except Lion-O are gone, Mumm-Ra switches Ma-Mutt with Snarf. Ma-Mutt poisons Lion-O, allowing Mumm-Ra to move in.

Vultureman builds a Thundranium[28] projector, capable of creating concentrated regions of Thundranium. When the ThunderKittens damage it, he damages their spaceboard, sending them off into danger. Wh…

Mumm-Ra learns about the Treasure of Thundera and the Sword of Plundarr (Jaga had beaten Ratilla, who owned the Sword, and then buried the sword deep underground), and he and Ma-Mutt ""travel back in …

Lion-O and the other Thundercats arrive and save Lynx-o and the Thunderkittens from Red Eye and Tug Mug. The Thundercats learn more about New Thundera, especially the dangerous places affected by the …

Mumm-Ra retrieves the Sword of Plundarr and the Thundercats arrive on New Thundera. While the Thundercats want to get the Sword and treasure, Snarf and Snarfer want to free their fellow snarfs. While …

Mumm-Ra tries to get away but the Sword of Omens breaks open the casket dropping the treasure all over the planet, and Snarf, Snarfer, and one other snarf escape. Mumm-Ra gives a false Book of Omens t…

Lion-O frees the Thundercubs from Mumm-Ra's spell and the Thundercubs safely leave New Thundera. Lion-O and Snarf must confront Mumm-Ra and get the Book of Omens. After they defeat Mumm-Ra, they ask M…

Mumm-ra finds the Totem of Dera (a part of the T-cat treasure) which has special healing powers and can bring inanimate objects to life. He gives it to Vulture-Man and the Mutants so they can make a d…

After looking at the Book of Omens, and seeing a picture of a necklace, Lion-O discovers that there are pictures of the Thundercats on the necklace. Jaga appears to Lion-O and tells him that he is loo…

Lion-O, Lynx-O, Snarf and Tygra go to the Crystal Canyon, thinking the Lunataks somehow got the Treasure of Thundera. While there, they encounter Aluro and Chilla. The two Lunataks trick the Thunderca…

Vultureman creates a device that plays around with Cheetara's sixth sense. She begins to see images that aren't real, and she soon begins to lose faith in herself. Meanwhile, the Lunataks enslave Pant…

The Thundercats capture the Lunataks and, tired of dealing with their evil ways, decide to exile the Lunataks to Exile Isle, an island in space far away from Third Earth. When the Lunataks arrive, the…

While trying to figure out a way to read the Book of Omens, Lion-O tries looking through the sword at the book. He is immediately drawn into the book, where a voice asks him if he has ""the key."" Lio…

Panthro, Tygra, and Cheetara return to New Thundera in the Feliner to find more of the Treasure of Thundera, but Mumm-Ra shoots the Feliner down and, as the Fog of Despair, sends them to the Canyons o…

Aluro invents a ""booster"" potion in hopes that it can make Sky Tomb able to fly to Thundera. It doesn't work, and he throws the potion into the forest. Then he notices everything in the forest has g…

On Thundera, Mumm-Ra creates the Locket of Lies and has Mu-Mutt plant it in the Valley of the Snarfs. Eggbert and Oswald Snarf find the locket and contact the Thundercats about it. When communications…

Tygra, Cheetara, and Bengali bring back a few more pieces of the Treasure of Thundera. Snarf is fascinated by a bracelet and takes it to wear around. He sees that everyone obeys his every command when…

Lion-O, Panthro, and Snarf set out to look for more pieces of the Treasure of Thundera, and Mumm-Ra sets a trap for them. He freezes them in the caverns of cold on Thundera. Meanwhile, back on third e…

Back visiting their old wreckage site, Lion-O and Snarf stumble upon the Thunder-scope, a legendary thunderian telescope that locates lost thunderians, and their belongings. Mumm-Ra, interested in the…

Mumm-Ra discovers the power of one of the pieces of the treasure of Thundera. The Double-Headed Dragon of Doom, or the Jade Dragon possess the power to entrap people in its stomach. The legend says th…

A bounty hunter known as Captain Bragg comes to Third Earth to help the Thundercats get rid of the Mutants and the Lunatacks. Capt Bragg tricks Wilykat in going with him and they first go after the Mu…

With the Mutants and Lunataks gone, the Ancient Spirits of Evil give Mumm-Ra until sunset to destroy all the Thundercats, and to prove they're not bluffing, they exile Ma-Mutt. Mumm-Ra spreads destruc…

The Ancient Spirits of Evil give new life to Mumm-Ra and Ma-Mutt, send them to New Thundera, and build a new Pyramid for Mumm-Ra. The Thundercats say goodbye to Third Earth and depart for Thundera, le…

More and more earthquakes are ocurring because of the malfunctioning Gyroscope. Meanwhile Lion-O recieves a distress signal from Thunderian refugees, and he, Cheetara, and Snarf go to find them. Mumm-…

Lion-O, Panthro, and the Thunderkittens take the Whisker, a new flying vehicle, to the Churning Rocks to rescue the Thunderian refugees who had called from there. The Thundercats get captured by Two-T…

Mumm-Ra sends Ma-Mutt disguised as Mandora to free the Mutants from Capt. Bragg's circus train and sends Bragg and Crowman falling into deep space. The Mutants are then ordered by Mumm-Ra to get rid o…

After another earthquake caused by Mumm-Ra ruins the new Cats Lair construction site, the Thundercats go to see Jaguara and confront Mumm-Ra. Unfortunately, Mumm-Ra puts up a force field over entrance…

The Ancient Spirits of Evil bring the Mirror Wraith to Mumm-Ra, and he disguises it as a child's toy. Mumm-Ra then intercepts a thunderian escape pod which carries in it a little girl. He gives the to…

Wily Kit and Kat are constructing a well for the New Cat's Lair on New Thundera. The Thundercats on New Thundera receive a distress signal from Thunderian refugees trying to find their way to New Thun…

Wily Kit and Kat, exploring New Thundera, stumble upon an Orb of Gold, and pick it up thinking that it is apart of their Heritage. Possessed by the power of the Golden Sphere of City, the ThunderKitte…

Jaguara cannot work New Thundera’s Gyro on her own. The Thundercats order a robot to aid her in running the Gyro. Screw Loose, a robot who specializes in Gyro’s, comes to New Thundera. Mumm-Ra manages…

Mumm-Ra summons Malcar, an ancient alchemist, to return from the dead. The alchemist returns old and weak, as he was when he died. Mumm-Ra takes him to the forest of youth to restore his youth and pow…

A convergence of the Moons of Plun-Darr causes a drought on Thundera. Panthro and Snarf go looking for water, then Ezuka, the flying Serpent of Dreary Canal wanting to get water itself, attacks Panthr…

Capt. Cracker and his mechanical parrot Polly land on Way-Out Back and free the Lunatacs and put Bragg and Crownan in one of the train's cages. They plan to go to Third Earth to attack it since most o…

Tygra, on a solo trip to New Thundera to meet the other Thundercats, decides to take a shortcut through a meteor shower. His ship is damaged, and he lands on an unexplored region of New Thundera. The …

Mumm-Ra has a new device, the Babylonian Barbarian Boiler, that he plans to use on Cats Lair. Ma-Mutt fools around too much and Mumm-Ra banishes him from the Pyramid. Later, the Thunderkittens, Snarf,…

From the Shadow Realm, the Shadowmaster contacts the Ancient Spirits of Evil (ASOE), telling them of how he captured Lion-O's father, Claudus, just before Thundera blew up. Then the Shadowmaster, thro…

An Ecology Inspector (EI) comes to Thundera to inspect the new Cats Lair. His ship uses the SWAN system (Space Way Airborn Navigations) to direct him to planets all over the universe. When he arrives …

Mumm-Ra orders Amortus, a being he banished to the Land of No Return centuries ago, to destroy Lynx-O. Amortus makes Lynx-O crash in the Thunderstrike, and then he touches Lynx-O's face. The spell fro…

Vultureman escapes from exile by hijacking a bookmobile. He finds a disk containing ancient history about two powerful evil forces on Third Earth: Mumm-Ra and his enemy Zaxx. Zaxx used a Rosencrest me…

The Thundercats use a new Tower signal to guide a Thunderian ship in; aboard are Baron Tass and Mr. Grubber, a devious pair of Thunderians. Later Lion-O sends Torr, Baron Tass and Mr. Grubber to get w…

New Thundera is being torn apart and the Thundercats must present certain artifacts at various dangerous locations that used to be beautiful places, then Lion-O must go into the book and give the Key …