Dimension Doom

An apparition of Wizz-Ra, an ancient Egyptian sorcerer, appears in the mirror in Cheetara's room, waking her from her sleep. While initially wanting to tell the rest of the ThunderCats about this strange occurrence, Cheetara decides against it, fearing that they might not believe her.

Meanwhile, Mumm-Ra watches Cheetara from his cauldron inside the Black Pyramid and explains to Slithe that Wizz-Ra possesses the Enchanted Golden Helmet of Pharnoor. The helmet gives its wearer the power to control minds. He recalls how many centuries ago he had tricked Wizz-Ra into getting banished and imprisoned in the Seventh Dimension for all eternity. However, once every seven thousand years, Wizz-Ra is able to return to Third Earth for one single day via a portal which coincidentally happens to be on the exact same spot as the mirror in Cheetara's room.

Mumm-Ra then brings the Fatatah Cheetah statue in his pyramid to life using his powers. He instructs the feline to bring him the enchanted helmet. The cheetah speeds to the Cats Lair and, avoiding detection, climbs into Cheetara's room and enters her body. At that moment, Wizz-Ra emerges from the mirror and the Fatatah Cheetah lunges on him. The cheetah then grabs his helmet and takes it to Mumm-Ra.

Inside Cats Lair, Lion-O and Snarf are unable to wake Cheetara from her sleeping trance. Wizz-Ra explains that she is under Mumm-Ra's power and only if he had his helmet could he break her trance. Thus the trio immediately head to the Black Pyramid. Once there, Mumm-Ra uses the enchanted helmet on Lion-O and starts taking control of his mind. Lion-O uses every ounce of his strength to summon the other ThunderCats before completely falling under Mumm-Ra's control.

Mumm-Ra orders the entranced Lion-O to throw the Sword of Omens into the Desert of Sinking Sands where it disappears without a trace. Lion-O then attacks Wizz-Ra but the sorcerer uses his magic power to stop Lion-O in his tracks. Shortly after, Panthro, Tygra, Wilykit and Wilykat arrive and they all fall victim to Mumm-Ra's mind control. Like Lion-O, they too attack Wizz-Ra and again he uses his magic to subdue them. After expending so much of his power, the weakened Wizz-Ra and Snarf retreat back to Cats Lair.

Outside the lair, Wizz-Ra and Snarf encounter Cheetara, who has broken free of Mumm-Ra's control. The three then head back to the Black Pyramid and sneak inside it undetected. While Mumm-Ra and Slithe are gloating over their success, Cheetara quietly moves the Vulture King statue so that the sun's beam coming from the roof hits its left eye. This fools Mumm-Ra into thinking that the day is over and Wizz-Ra has returned to his dimensional prison and so he removes the helmet. Snarf quickly grabs the helmet and gives it to Wizz-Ra who uses it to free the ThunderCats from Mumm-Ra's control and then blasts Mumm-Ra with his magic, causing the mummy to retreat into his sarcophagus.

With the day almost over, Cheetara helps Wizz-Ra to get back to the portal before time runs out for him. Wizz-Ra then thanks Cheetara and bids her farewell before entering the mirror and returning to his dimension. Lion-O calls the Sword of Omens and it emerges from the sands and flies into his hand.