Criminals in the city of Fuuto transform into super monsters known as "Dopants" by using USB-like gadgets called "Gaia Memories," causing chaos in an otherwise tranquil city. Shoutarou Hidari, a self-described "seasoned investigator," is one of the heroes who employ "Gaia Memories" to combat these crooks. Together with his ingenious partner Philip, Kamen Rider W, the renowned hero of Fuuto City, is created.