When a new threat from outer space called Galaxy King arrives on Earth seeking an equation for a new type of energy, Skyrider, and the other seven Kamen Riders join forces to fight off the new foe and the armies of Neo-Shocker.

The Dogma Kingdom attacks the Matagi (mountain tribe) village of Yamabiko to steal the sacred Flying Dragon Fortress and wreak havoc all over Japan. Six children from the fallen village take refuge in a nearby town, keeping their identities as Matagi citizens a secret. Kamen Rider Super-1 must protect these children from the Dogma Kingdom, as they hold the secret to the Flying Dragon Fortress' weakness.

The Badan Empire killed Ryo Murasame's older sister, and he had been cybernetically remodeled into ZX. However, he regained himself after an accident and stood up fearlessly.