Bad boys, bad boys, watcha gonna do? Watcha gonna do when they come for you?
We open on a blue metal container with prominent “danger” warnings. Lion-O and Snarf, walking through some tall grass, stumble across it. Snarf, by the way, is carrying a really conspicuous bag on a string around his neck.
Lion-O hears some noises from inside, and decides to open it up, supposedly because someone may be hurt, but really because he’s just curious. He tries to only open it a crack, but the people inside bust the door wide open. Three individuals escape. The first is a guy in a cape with weird tubes sticking out of him.
The second is some kind of speedy robot.
The third is a mantis-like creature with metal clamp hands (he may be a robot, too, it’s hard to say).
At first it appears that the last one is quite friendly, until Snarf notices that his coin purse (with his collection of tricentennial Thundera half-dollars and his lucky Jaga penny) has been stolen. Lion-O is skeptical, until Snarf points out that the Sword of Omens was also taken. They try to chase the thief down through the grass, but can’t find him. Just then, from out of the sky, someone flies in on a space-motorcycle.
She’s upset because Lion-O has just released three of the universe’s most wanted evil-doers. She had left them there until they could be transported to the Gray Penal Planet. She then calls Lion-O an “inexperienced oaf” and Snarf a “fuzzy shrimp”. Snarf wants to know who she is, so she flashes her badge and introduces herself as Evil-Chaser First Class Mandora, Interplanetary Control Force.
She then demands the Lion-O and Snarf help her apprehend the escaped prisoners, explaining that she’ll need their local knowledge. She wants to start first with Plutar, who she expects will seek out gassy swamps. Lion-O figures that The Living Ooze would be the best match to that description. They all pile on her space-motorcycle and set off to find it.
Mandora explains that everything Plutar touches eventually dies: trees, flowers, animals. Cut to Plutar (the guy in the cape), who is killing everything he touches.
The Living Ooze, who turns out to be more anthropomorphic than I expected, is upset that someone is polluting his streams and killing his trees, since that’s his job.
Plutar and The Living Ooze go back and forth for a while on the subject of who’s a bigger badass when it comes to killing things, but Plutar eventually proposes teaming up to turn Third Earth into a wasteland (it’s not entirely clear why he wants to do this, but I guess he’s kind of like a Captain Planet style eco-villain who believes that destroying the environment is its own reward).
The biggest kink in this plan is that Plutar knows the evil-chaser is hot on his trail. The ooze is skeptical that an evil-chaser can hurt him, but Plutar informs him that Mandora has a weapon capable of destroying both of them. They figure they can team up and trap her in the valley.
Cut to Mandora, Lion-O, and Snarf on the space-motorcycle. Lion-O points out The Living Ooze at a bend in a river. Mandora figures she’ll need to land on the riverbank next to the ooze. She tries is, but the ooze rushes under her as she’s putting down, and she skids out of control.
They’re all thrown off and trapped by the ooze. Lion-O almost breaks free, but Plutar nails him with some kind of gas attack, which knocks him back down into the ooze.
Mandora, still projecting that she’s in control of the situation, warns Plutar that resisting an officer is a punishable offense, and tells him to turn himself in. Plutar scoffs that Mandora can’t do anything, since they’re all trapped in the ooze. Mandora, however, slips out of her uniform (she’s got an off-the-shoulder body-suit underneath) and out of the ooze’s clutches to make her way back to her bike. She whips out what Plutar calls “the enzyme catalyzer”. The ooze makes a valiant attempt to get her.
Unfortunately for Mandora the weapon isn’t working because some goop got in the filter. She uses some eye-beams to make some emergency repairs.
With her weapon working again, she’s able to instantly dissolve the ooze, and poses in triumph.
Plutar tries to jump her from behind, but she drops to the ground and zaps him.
He ends up sparkling clean. Lion-O asks what the gun shoots, and Mandora explains that it’s an ancient formula, now a closely-guarded secret: soap. Mandora puts Plutar on the back of her space-motorcycle and takes him back to the cell-sled. Lion-O hears a familiar noise, that speedy robot.
Snarf is concerned that it will run over a deer, but Lion-O figures he’ll just drop the giant nearby boulder onto the robot before that happens.
They get him, and the deer runs to safety, but the robot gets back up and is pissed off. Apparently the robot’s name is Burnout. He tries to run Lion-O down, but Lion-O uses a rope fired from one of the knuckles of the Claw Shield to snag a tree branch and get out of the way. Burnout charges again, but Lion-O leaps out of the way. He charges again and Lion-O throws the Claw Shield underneath him to knock him over. Mandora flies in and takes stock of the situation, and decides to use her boomerang.
She misses, but Lion-O snags the boomerang and throws it at Burnout again. The boomerang dispenses some paint onto Burnout’s eye, which causes him to lose control and drive into the river.
Mandora likes the cut of Lion-O’s jib, and thinks he might make a good evil-chaser. She says that catching Quick-Pick won’t be as easy as this was, because he has a reputation as a master escape artist. Mandora plans to use a tracker to hunt Quick-Pick down while Lion-O takes Burnout back to the sled-cell on the space-motorcycle (wasn’t it a “cell-sled” earlier?).
Mandora activates another tracker on the space-motorcycle that will let Lion-O find her once he’s got Burnout locked up. Lion-O and Snarf start flying back, and Mandora uses her tracker to find Quick-Pick. She tracks him to a sandy area, but doesn’t see him, even though the tracker says she’s right on top of him. As she’s looking, she’s sucked into the ground!
As Lion-O puts Burnout into the cell-sled-cell, an alarm starts beeping on the space-motorcycle. Plutar tells him that “it means the lady’s had it. She’s probably been zapped out at last.” Lion-O hops on the bike and flies off to the rescue.
Cut back to Mandora, who has been captured by boar-people.
They toss her in with Quick-Pick, who was presumably captured earlier. He refers to their captors as mud-hogs and explains they don’t have a language except for snorting, although they do have a king.
The king of the mud-hogs has confiscated the Sword of Omens and Snarf’s coin-pouch from Quick-Pick, and is wearing them on his belt. The mud-hogs take Mandora and Quick-Pick up to the ceiling of their underground lair, where they have holes that are just big enough for someone’s head to fit through. Above ground, with Quick-Pick and Mandora’s heads sticking out of holes, a vulture flies around, menacing them. Lion-O comes flying in on the space-motorcycle and scares it away.
Mandora warns Lion-O to stay back, but he doesn’t listen, and he and Snarf get captured by the mud-hogs, too.
Back underground, Lion-O explains that if he could get the sword, he’d be able to get them all out of trouble. Mandora suggests that Quick-Pick do something about that, as he’s an escape artist and pickpocket. He’s reluctant, but Lion-O talks him into it. He sneaks up and grabs the sword off the king’s belt.
Unfortunately, the mug-hogs get to him before he can do anything with it. Lion-O suggests throwing it, which he does, and Lion-O bursts his bonds and grabs the sword. “Thunder, thunder, thunder, Thundercats, HO!” The giant Thundercats symbol shoots out of the Eye of Thundera, through the cavern roof, and into the air. The other Thundercats see it, and do kind of a roll-call as they pile into the Thundertank. “Tygra ready, ho! Cheetara Ready, ho! Wilykit and Kat, ho! Reactor Engaged, Traction locked, all go!” (That was Panthro at the end).
The mud-hogs have surrounded the former prisoners, and Mandora tells Lion-O, expecting to be killed in moments, that he would make a great evil-chaser. But before they are all brutally killed, the Thundertank bursts through the wall!
It scatters the mud-hogs, and Tygra wonders if they should use the cat-blaster on them (I wouldn’t think so, since they’re not cats. Maybe the mud-hog-blaster would be a better choice…). Panthro, however, figures that they’d be more afraid of the headlights, and flips on the high-beams, blinding them.
In the coda, Lion-O, Cheetara, and Wilykit seem especially concerned that Snarf will “say it”. Panthro comes in with Snarf’s coin purse, which Mandora recovered, which pleases him greatly, although its sets him off on one of his lectures. And apparently they were all concerned that Snarf would say “you’re too curious” to Lion-O, which they all find hilarious for reasons that escape me.