An ordinary young man, Lin Yu, accidentally traveled to the world of Kamen Rider. Carrying the mysterious belt of twin fusion and an unknown silver object, he was involved in a crisis related to the survival of the parallel world - the mysterious organization attempted to open the dark passage and release the "World Eater" to destroy the multiverse.
In order to stop the conspiracy, Lin Yu fought side by side with the passionate knight Yusuke Godai and the calm strategist Mr. Ichijo. He also received help from the Civilian Self-Defense Corps (members such as Akai) and the World Guardian Association. From the intelligence handover in the abandoned bell tower to the battle to close the passage at the ceremony site, they faced the leader of the organization that controlled dark energy and the scale monster who could fold space. In a desperate situation, they unlocked new abilities of the belt and discovered the secret of "twin power" hidden in the ruins of ancient buildings.
When a powerful enemy comes with black flames, and when the fluctuations in the belt hint at a greater conspiracy, Lin Yu is no longer a passive traveler - he holds the crystal ball of insight and carries the trust of his partners. In the choice between "guarding" and "truth", he gradually reveals the truth about time travel, the origin of the belt, and the ultimate crisis behind the "World Eclipse" that can subvert all parallel worlds. This is not only a battle, but also a journey of growth about responsibility and bondage.
