II. Mighty Morphin
First Episode: “The Mutiny, Part 1″
Sentai: Tensou Sentai Dairanger
“Lord Zedd, emperor of all that he sees, arrives at the Moon Palace of Rita Repulsa, where he takes her place and throws her into a space dumpster again. He then begins to attack the Power Rangers with Pirantishead, a stronger monster than the Rangers are used to fighting. Pirantishead freezes four of the Dinozords and takes control of the Tyrannosaurus Dinozord and the Dragonzord. The Rangers need to upgrade their Dinozords into stronger Thunderzords, which can become the Thunder Megazord. They defeat Pirantishead and give Lord Zedd his first defeat.
Soon after that, Lord Zedd realizes he needs to destroy the Green Ranger. He does so with a special Green Gem, using it to take away the Green Ranger’s powers permanently since he had limited powers after Rita had taken away most of them in Season 1. The Green Gem also powered up the Dark Rangers, but when Tommy smashed it, the Dark Rangers’ powers were transferred back to the regular Rangers. Lord Zedd thought he’d already won, but Zordon made a White Ranger to aid the Rangers in battle. The White Ranger turns out to be Tommy. Then the Rangers make some new friends, Rocky, Aisha and Adam. They discover the Rangers’ identity, and become allies of them.
When Jason, Zack and Trini are selected to go to the Peace Conference in Switzerland, they need to find three replacements for them as Rangers. They need to find The Sword of Light to make the power transfer, the sword located on a deserted planet. Lord Zedd wants the sword too and introduces Serpentera, his personal Zord. The Sword is retrieved and taken back to Earth. Serpentera runs out of power and is put away for now. The retiring Rangers choose three new Rangers, and come up with Rocky as the Red Ranger, Aisha as the Yellow Ranger and Adam as the Black Ranger.
Rita Repulsa had returned to Earth when the Rangers were fighting Nimrod and Tommy made his debut as the White Ranger, and fell into the hands of Bulk and Skull, but the Rangers put her back into space. She then again returns to the Moon and, with the help of Finster, uses special moon mud to retrieve a younger face. She then puts a love potion into Zedd’s Rejuvenation Chamber and he falls in love with her. They get married and fight the Rangers together, now stronger than ever.”
– Taken from http://powerrangers.wikia.com/wiki/Mighty_Morphin_2