The Zeo Rangers pursue the maveric Zeo Megazord in the Super Zeo Megazord, meanwhile, Finster is able to locate the Impursonator and sends it back to Earth, where it immediatly infiltrates and takes control of the Super Zeo Megazord.
Cog Changer, in the cockpit of the Zeo Megazord, soon comes to blows with Impursonator, and the two Zords do battle, threating all of Angel Grove.
Meanwhile Bulk and Skull prerpare for a special exam that will officially give them full fledged Detective licenses, beleiving the current monster alert to be a "test of thier nerves" they ignore the alarm and concentrate on the exam, and it's because of this "act of bravery" alone that they receive extra points to become Detectives.
Katherine comes up with a strategy to take bvack both Megazords, Tommy, Adam, and Rocky lure Impursonator out of the Supoer Zeo Megazord, and Katherine and Tanya take out the cog controlling the Zeo Megazord, they then oust Cog-Changer from the Megazord cockpit. Rita pulls Impursonator out of battle and berates her for not putting a dent in the Rangers, with both Zords back under thier control, the Rangers turn back to the problem of Billy's aging, only water from the eternal falls of Planet Aquitar can save him now, an old girfreind of his, Cestria, arrives with some of this water, but it is not enough.
Billy is forced to depart for Aquitar to receive more treatment whilst the Rangers face off against Cog Changer and the Impursonator (sent back by a forgiving Rita) as well as a Cog army, back in Angel Grove, however, this time the Rangers have the Aquitian Rangers on thier side, and they defeat the Cog army. Lord Zedd, Rita, and Mondo make thier monsters grow, Impursonator and Cog-Changer then fuse together to create a new threat, but they/it are destroyed thanks to a handy Power Ranger-style game of catch and toss involving the Zeo Megazord, the Red Battlezord, the Super Zeo Megazord, and the Warrior Wheel. The Zeo Rangers thank the Aquitian Rangers, and back at the Power Chamber, the Rangers bid a tearful goodbye to Billy as he communicates with them from Aquitar, having chosen to remain with Cestria