The Power Rangers, Adam, Kimberly, Billy, Aisha, Rocky and Tommy (along with Sora, Donald, and Goofy) participate with Bulk and Skull in a charity sky dive for Angel Grove in anticipation of Ryan's Comet which will be passing near the planet in two days. After the heroes jump, Bulk and Skull finally work up the nerve to dive as well, landing in the middle of a construction site in midtown. Before they are reprimanded the construction workers are distracted by a giant egg that had been uncovered where they were digging. The unearthing of this egg alerts Zordon who contacts the heroes; he explains that 6,000 years ago he tricked a shapeshifting being known as Ivan Ooze by trapping him in the egg and buried it to prevent him from taking over the universe. He sends them to recover the egg before it is opened, but Rita Repulsa, Lord Zedd, Goldar, and Mordant find the egg and release Ivan before the heroes arrive. Ivan sicks several subordinate "oozelings" on the heroes and departs to destroy the defenseless Command Center, leaving Alpha incapacitated and Zordon outside of the timewarp tube that keeps him alive. With the destruction of the Command Center having disabled the Rangers' morphing powers, Alpha sends them to the planet Phaedos in search of a greater power to defeat Ivan and save Zordon. After they leave, Ivan traps Rita and Zedd in a snowglobe; not wanting to meet the same fate, Goldar and Mordant submit to him.
Ivan decides to recruit the parents of Angel Grove to dig up the Ectomorphicon Titans, massive zord-like machines that were buried long ago. In order to do this, he takes the disguise of a carnival wizard and gives out free jars of ooze to the children of Angel Grove, one of whom is a young friend of the rangers Fred Kelman. Fred's father discovers the ooze, which promptly hypnotizes him, along with the rest of the parents, into working for Ivan. Fred discovers this and follows the parents to uncover Ivan's true colors. Meanwhile, the heroes arrive at a plateau on Phaedos and after facing an attack from Ivan's minions, the Tengoo, they meet Dulcea a warrior who wants to help Zordon by leading the heroes to the great power. She teaches them to harness their animal spirits, and directs them to a monolith which houses the power. The heroes overcome many deadly obstacles and uncover the power along with new zords to match their animal spirits. With their power restored, they return to Earth to face Ivan.
Having restored his Ectomorphicon machines, Ivan orders the parents to leap to their deaths at the construction site; Fred recruits the now-parentless kids to help him save them. The heroes arrive and summon their zords to stop the Ectomorphicons, saving the kids who are nearly killed in a monorail derailment allowing them to continue their mission as the Rangers battle Ivan's machines. When they destroyed one of his two machines, Ivan merges with the other becoming a massive robotic version of himself. The Rangers form the Ninja Megazord, but are heavily outmatched in the fight. Billy suggests they drag Ivan into the path of Ryan's Comet to destroy him. They form the Ninja Falcon Megazord and trick Ivan into chasing them into space and with a trick maneuver from Aisha, they are able to safely avoid the explosion when the comet destroys Ivan. His destruction reverses the hypnotic effects of the ooze, and the parents, who have been stalled by the Fred, Bulk and Skull, and the other kids, are saved. The heroes return to the Command Center where they learn that Zordon had died. Tommy suggests using their powers to revive him, and they are able to do so, restoring the Command Center and his timewarp tube all at the same time. In a celebratory festival, Bulk and Skull are offended that the Power Rangers are given credit for saving the city yet again even though they legitimately had a part in helping to save lives, but their embellished tales only lead to laughter from the teens.
Meanwhile, in Rita and Lord Zedd's Moon Base, Goldar has decided to proclaim himself "King Goldar, The Emperor of the Universe" but his and Mordant's celebrations are cut short when a very irritated Rita and Lord Zedd enter the chamber, growling at their turncoat behavior. Goldar and Mordant look at each other and say "Uh-oh" before the screen goes black.