When the Dopants began to appear in the windy city of Fuuto, young Shotaro was Sokichi's assistant and tried to follow his footsteps to become a great detective, while Sokichi secretly fight against the Dopants as Kamen Rider Skull. It was when the Narumi Detective Office received a phone call that spoke of a request from hell, Sokichi and his team were dragged into the fateful night! How were the Gaia Memories created? How did Kamen Rider W's battle begin? Shotaro and Philip, the duo detectives who became Kamen Rider W, their full story will finally be revealed...