The Power Chamber has been destroyed by Divatox, and the Turbo Powers are gone. As the Rangers hide in the ruins of their former base of operations, Divatox leaves for deep space, where a federation of evil leaders is called together for an urgent summit. Among the familiar faces: Lord Zedd, Rita Repulsa, Master Vile, and the Machine Empire. Their new leader, Dark Specter, has kidnapped Zordon, and plans to drain his powers for evil. He has placed princess of evil Astronema in charge of destroying the Rangers.
United to foil Dark Specter's plot, the Power Rangers must travel into deep space and free Zordon before his powers become Dark Specter's. They acquire a NASADA spacecraft and take off, leaving Justin behind with his father. In space, they meet a Red Ranger, who gives them powers and allows them to team up with him against Dark Specter.
On their search for Zordon, the Rangers encounter their old friend the Phantom Ranger, who gives Andros a disc which will give him control of the Delta Megazord. Some time later, Andros retreived keycards from an alien casino, which showed him the location of the Mega Voyager, five spacecraft which assembled into a Megazord.
When the Megaship landed on an alien world, it was broken into by some hostile aliens, who inadvertently set free Zhane, the Silver Ranger, who was in a cryogenic sleep on the ship, healing from wounds. Zhane left the Rangers a short while after, to help some KO-35 rebels who were under attack. The rebels gave Zhane the Mega Winger, which he used to return to the Rangers when they needed him.
Andros discovered that Astronema was actually his long lost sister, Karone, kidnapped by Darkonda many years ago on KO-35. When she also found out the truth, she thought twice about being evil, and eventually joined the Rangers, only to be once again kidnapped by Darkonda and turned evil by an electronic attachment on her head.
During their last battles, the Rangers lost the Delta Megazord, the Mega Winger, and the Mega Voyager. With only the Astro Megazord left, the Rangers had to find a way to defeat the forces of evil, which had launched a full scale assault on the entire universe. Andros had to destroy Zordon's tube, which released a wave of energy which swept across the universe, putting an end to the Machine Empire, Zedd, Rita, Divatox, and Astronema, who had become Karone once more, and joined the Rangers back to Earth.