Three years ago, Gentoku Himuro, head of the Touto Institute of Advanced Matter Physics, tries to convince his old friend and Touto Prime Minister aide, Koji Hotei that Touto needs to strengthen their military in order to face the threat Hokuto and Seito represent. Hotei however, does not listen. It is then that Gentoku is made aware of a certain researcher. Takumi Katsuragi was performing tests on human subjects using the Nebula Gas and it was going well, until his chief officer, Himuro, gets knowledge of what he has been doing and suspends his project. Soon after, Katsuragi gets scouted by a man who was interested on his work, and resumes his research for the Nebula Gas under the Namba Heavy Industries. How will this research affect the lives of those who were used as test subjects? (Source: Kamen Rider wikia)