On Primus, the Scientists begin to try and fix the Trithuseum Generator, while bickering and showing off amongst themselves. U.R., the robot, assists the Scientists by keeping them cool in the Priman heat. When Krex orders U.R, to cool them down, the disobediant robot freezes him in a block of ice. Maldoc falls asleep while the others are working.
After He-Man returns with the crystals, Flipshot begins boasting about defeating the Mutants. After a report of an attack on the floating city of Levitan, He-Man and the others rush off to defend the city and leave the Scientists to their work. They soon discover that Levitan is perfectly safe, and that they were lured away from the Scientists, who are captured by the Mutants.
When Krex asks for a wrench, he find himself clutching a mechanical tentacle, turning around to see Slush Head, whouses his tentacles to grab a screaming Krex and lift him up into the air. Slush Head is very imposing here, towering above Krex, and bashing U.R. out of his way.
When Master Sebrian, Drissi and Mara discover that the Scientists have been captured, He-Man returns with Caz, after realizing that Skeletor has tricked him. Drissi is relieved when she sees that Caz is all right.
Aboard the Mutant Mothership, Slush Head has brought back the Scientists, and marches onto the bridge, putting his hand across his chest in salute to Skeletor and Flogg. Skeletor than attempts to interrogate the captive Scientists and discover all they know about the shield around Primus - but they are too terrified to respond to his questions. The only thing Skeletor learns, is that the four Scientists were the ones who originally built the Trithuseum Generator. Skeletor becomes enraged that he couldn't extract anymore information from the Scientists. He then informs the Scientists that they are heading to the Quagmi Swamp on Denebria and slams down his Havoc Staff, causing him to disappear with a puff of black smoke.
On Primus, Gleep notices his ‘buddy’ U.R. trapped under the wreckage Slush Head trapped him under earlier. He-Man shows his strength by picking up the wreckage and tossing it away, then picks UR out of the mess. Fortunately, U.R. has a homing device to track the scientists with.
He-Man, Hydron, Flipshot and the Robots use the Starship Eternia to follow the Mutants to the Quagmi Swamp, on Denebria. On the way to Denebria, Hydron refers to the Quagmi Swamp as ‘the stinkhole of the Tri Solar Galaxy’. He-Man looks in the weapons compartment aboard the Starship Eternia, pulling out a futuristic bomb and detonator.
The Mothership arrives in the Quagmi Swamp, the swamp itself is very creepy and filthy looking, with green mist floating in the air. Hoove and Karatti comment on the disgusting smell, but Slush Head is thrilled, the Quagmi Swamp is home and he’s glad to be back. Slush Head takes his helmet off and jumps into the swamp, swimming around in the merky waters. The Scientists are brought out of the ship, with Skeletor and Flogg treating them like cattle, Flogg even uses his Hurricane Whip to get them to speed up, as Skeletor shoves them with his staff.
He-Man, Hydron, Flipshot and the robots arrive in the Starship Eternia. Flipshot uses his jetpack to fly across to the Mothership and plant the bomb, that He-Man discovered. Next, the group then become trapped in a storm in the swamp, where the Sorceress appears before He-Man to give him a clue to what he must do. After she disappears, He-Man uses his sword as a beacon to clear the way through the stormy swamp. He-Man and the others ultimately find the Scientists, who are being guarded by Skeletor, Flogg, Slush Head, Hoove and Karatti.
Meanwhile, the Scientists have discovered that the trees in the swamp stop sneezing, and characteristically plan on using this to become heroes on Primus, they are rescued by He-Man and the others as Skeletor reveals himself. The following fight between the Mutants and the Galactic Guardians is very action packed. Flipshot uses his jetpack to quickly flying out of Hooves way, as he swings a tree he has uprooted at him. Hydron fights Karatti, who demonstrates his martial arts skills and ultimately overpowers Hydron, showing just how tough the bad guys here are. Hydron and Flipshot are more intelligent though, and trick their opponents into defeating themselves. Flogg and Slush Head take on He-Man, who disarms them easily. When Slush Head loses his gun, he begins to use his metal tentacles on He-Man. In a clever move, He-Man ultimately tricks Flogg and Slush Head, by causing them to become entangled with Flogg's Hurricane Laser whip and Slush Head's tentacles. Skeletor becomes furious and decides to enters th fray, by diving down and capturing Gepple, holding him hostage and threatening to kill him if he tries to escape. He-Man stops Skeletor, by revealing that they have planted a bomb back at the Mothership. Unlike Flogg, who cares for the Mutant Mothership, Skeletor, who doesn’t care about the ship and realizes he has beaten. Skeletor slams down the Havoc Staff and disappears in a black puff of smoke, leaving Flogg and his Mutants behind. He-Man promises Flogg he will not detonate the explosive as long as Flogg let's them leave the swamp. Flogg reluctantly agrees, and He-Man and the others return to Primus, where the boastful Scientists try and take all the credit for the defeat of the Mutants.
Original Air Date: September 13, 1990
Characters: He-Man/Prince Adam, Master Sebrian, Mara, Hydron, Flipshot, Drissi, Caz, Gepple, Alcon, Maldoc, Crax, Gleep. U.R., Skeletor, Flogg, Slush Head, Hoove, Karatti, Crita
Magic/Objects/Weapons: Sword Of Power, Trithuseum Generator, Trithuseum Crystals
Locations: Quagmi Swamp, City Of Levitan Vehicles: Mutant Mothership, Starship Eternia