The Best Episodes Written By Leonard Starr

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 and Mumm-Ra attempt to attack Lion-O to possess the Sword, but miserably fail.

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 capture the Eye of Thundera. Due to the attack, the Thundercats find themselves on a distant planet. A grown-up Lion-O must save his Thundercats from the Mutants on Third Earth.

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 disappears, leaving Wilykit - who was looking for another way in - close to panic. She and Lion-O (alerted by the Sword of Omens) must now brave the Tower's potentially lethal traps in order to rescue Wilykat.

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 form an alliance. Mumm-ra attacks the Berbil village, but the Thundercats save it. In return, the Ro-Bears help the Thundercats to build Cats' Lair, a new base for the Thundercats.

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-Men from the Mutants.

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.

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

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, Tartara, captures the Arrietta bird, whose songs enchant the Berbils' harvests. Lion-O, upset with her selfishness, goes off to save the bird, but gets caught and put under an evil spell. Snarf, managing to slip through the crystal queens defenses, saves Lion-O and frees the Arrietta bird.

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 title. His first test is to beat Panthro in a duel to test his strength.

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 short time period. Lion-O takes a shorter but more dangerous route to make up for Cheetara's advantage.

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. He manages however to avoid their traps. In order to beat them through the maze, Lion-O plays their own tricks on them, and tricks them into losing the race through the maze.

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

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

Mumm-Ra plays deception with the Thundercats when he (disguised as Jaga) tells Lion-O that the Thundercats at the Tower of Omens will rebel and take Third Earth for themselves. Then he disguises himself as a Tuska warrior and asks the Thundercats at the tower for help. Ben-Gali, Pumyra, and Snarfer go to investigate while Lynx-O calls on the others to help, but Lion-O warns the others of their possible treachery, but Panthro, Cheetara, and Snarf go anyway but somewhat cautious. When they meet, the Tuska warrior "accidentally" causes the newer Thundercats to attack. He then disappears and the Thundercats start fighting each other. Meanwhile the Lunataks invade Cats Lair and the Tower of Omens. Lion-O must call on the Thundercats hoping they'll stop fighting each other to defeat the Lunataks and Mumm-Ra, which they do.

Mumm-Ra tells Aluro that the Egora Talisman will give whoever possesses it the power of extreme self-confidence. Aluro finds the talisman and uses it, along with his own powers of hypnotism, to "take away" the Thundercats' self-confidence, leaving them hopeless and confused. Only Snarf remains and it is up to him to defeat Aluro and restore the Thundercats.

Mumm-Ra plans on using the legendary Mask of Gargon to free a sleeping child in the hills of Elfshima to use against the Thundercats. When Chilla and Tug Mug fail to get the mask because it turned them to stone, Mumm-Ra summons it and decides he needs the Eye of Thundera so that the mask can use sight beyond sight to awaken the giant child. Lynx-O warns the Thundercats of the mask and the sleeping child, but Lion-O, Panthro, and Willa still go to the pyramid, but are turned to stone by the mask. Mumm-Ra then uses the Eye of Thundera and the mask to awaken the giant. But Lynx-O and Ben-Gali in the Thunderstrike defeat the giant and the mask gets smashed apart restoring everyone who had been turned to stone, and the Eye of Thundera burns the book that contained the mask's terrible secrets.

The Madd Bubbler, an ancient creature of third earth who lives in an old Thundrilium mine on hook mountain has the power to turn all creatures into evil beings, and making people accept his modo - "destroy, or be destroyed". He manages to seduce the Luna-tacs to fight against each other, and afterwards Panthro, Tygra, and Cheetarah. They fall under the bubblers power and begin fighting each other to the death. Lion-O, observing these occurrences through the sword of omens finds out from Jaga that snarfs are not capable of evil. He summons Snarf and Snarfer and tell them to retrieve the Thundercats from the mine so that they can be returned to their normal selves.

Mumm-Ra summons the Berserkers and coats their armor with Thundrainium and sends them to attack the Thundercats at the Tower of Omens. Realizing that their armor is coated with Thundrainium, the Thundercats at the tower need help and Lion-O and Tygra rescue them. They create a windstorm to rub off the Thundrainium and the Berserkers retreat. Meanwhile the Lunataks invade Cats' Lair and the Thundercats must rush back to save the Thunderkittens and Snarf who are being held as the Lunataks' slaves.