The transmigator Shirahashi and Ohma Zi-O met by chance on a certain occasion. At Ohma Zi-O's request, Shirahashi began to re-enact Kamen Rider history in various worlds, saving and mending the Kamen Rider worlds.
Time flew by, and Shirahashi completed his mission, becoming the second Ohma Zi-O. He used the freshly acquired, scorching hot power of Ohma to restore the worlds he had thrown into chaos. He then found a quiet place, ready to begin his recluse-like retirement.
Next, he realized something seemed amiss. In each world, a certain... appeared.