The only hope of regaining control of the Dinozords from Pirahntishead is Billy's latest invention. If they can get it to work, Zordon will then infuse each of the main five Dinozords with a lightning charge, causing them to morph into the mighty new Thunderzords! The Red Dragon, the Yellow Griffin, the Blue Unicorn, the Black Lion, and the Pink Firebird can then come together to form the Thunder Megazord. But will it be enough to defeat the power of Lord Zedd's Pirahntishead? Meanwhile, Bulk & Skull, saved by the Rangers for the umpteenth time, begin their quest to discover the secret identities of the Power Rangers!