The son of Lord Zedd and Rita Repulsa, Thrax, unites all four Corona Aurora-seeking factions of villains into a new Evil Alliance. When they manage to overwhelm the Overdrive Rangers, their connection to the Morphing Grid is severed, and their powers destroyed. With the gems still needing protecting, Sentinel Knight assembles a team of replacement Rangers, made up of members of previous (or future) teams of Power Rangers.