Power Rangers Zeo begins immediately after the events of Mighty Morphin Alien Rangers, where Tommy and the other Rangers (Adam, Rocky, Tanya, Katherine and Billy) witness the destruction of the Command Center. After recovering, the powerless Rangers discover the Zeo Crystal intact in the rubble—apparently dropped by Goldar and Rito Revolto. The Crystal guides them to a portal, which takes them deep underground to the Power Chamber where they find Zordon and Alpha 5 waiting for them. The Mighty Morphin Power Rangers become the Zeo Rangers, a new team of Rangers powered by the Zeo Crystal. The four remaining Mighty Morphin Rangers, Tommy, Adam, Rocky and Kat become Zeo Ranger V — Red, Zeo Ranger IV — Green, Zeo Ranger III — Blue and Zeo Ranger I — Pink respectively and Tanya Sloan joins the team as Zeo Ranger II — Yellow, while Billy chooses to become their technical advisor rather than continuing as a Ranger.
The Machine Empire, led by King Mondo and Queen Machina, enters Earth’s solar system, seeking to conquer Earth, with the Zeo Rangers serving as the only opposition. Many, even Rita Repulsa and Lord Zedd, are forced to flee to the M51 Galaxy under the threat of destruction. Unbeknownst to anyone, Rito and Goldar – now amnesic – are left behind on Earth. They are taken in by Bulk and Skull, who have them serve as butlers. Meanwhile, Bulk and Skull continue to be members of the Junior Police Force until Lieutenant Stone is dismissed, when Bulk tries winning the heart of the chief’s daughter. Quitting as a show of respect for Stone, they join him at his new detective agency…
