Ordinary young man Lin Yu accidentally transmigrates into the Kamen Rider world, carrying a mysterious belt that fuses two entities and an unknown silver object. He is swept into a crisis threatening the survival of parallel worlds: a mysterious organization plans to open a passage to darkness and unleash the World Eaters to destroy the multiverse.
To stop the conspiracy, Lin Yu fights alongside the hot-blooded Kamen Rider Yusuke Godai and the composed strategist Kaoru Ichijo. He also gains the support of a civilian self-defense group, including Akai and the others, as well as the World Guardians Association. From an exchange of intelligence in an abandoned clock tower to a battle to close the passage at the ritual site, they face an organization leader who controls dark energy and scaled monsters capable of folding space. Against all odds, Lin Yu unlocks new abilities in his belt and discovers the secret of the “twin powers” hidden in ancient ruins.
When a powerful enemy arrives bearing black flames, and fluctuations in the belt hint at a greater conspiracy, Lin Yu is no longer a passive traveler between worlds. With a crystal ball of insight in hand and the trust of his companions on his shoulders, he must choose between “protection” and “truth” as he gradually uncovers the truth behind his transmigration, the origin of the belt, and the ultimate crisis behind the World Eaters, a threat powerful enough to overturn every parallel world. This is more than a battle: it is a journey of growth about responsibility and the bonds between companions.
