[1] On the planet of Edenoi, King Lexian grants his grandson Dex the Masked Rider powers before sending him to Earth in a meteor.
After Dex explains the story of his origins to the Stewarts and why he needs to fit in with the humans on Earth, Count Dregon—the series' main antagonist—sends an Insectovore called the Destructosphere to destroy the city at dawn.
Dex narrowly escapes defeat at the hands of Destructosphere, and is advised by his grandfather, King Lexian, to create new allies for himself, resulting in the birth of Combat Chopper and Magno.
But later, Masked Rider and his new allies must battle a trio of Count Dregon's Maggots when they are unleashed upon the local Leawood High School, as well as the Insectovore Beetletron.
Dex must team up with the Masked Rider Warriors dispatched by King Lexian to save the city from this new menace.