In the Wind City "Wind City", Shotaro Sae, his partner Philip, and the director Akiko Narumi run a detective agency. Behind the seemingly peaceful Wind City, a mysterious organization circulates "Gaia Storage Bars of Evil" underground that can turn ordinary people into Dopant. Everyone in the "Sonosaki Family", the core of the mysterious organization that caused many bizarre events, has a great influence in Wind City. Shotaro and Philip, who challenged the Dopant to cause bizarre events, used six "Gaia Storage Bars" to transform into Kamen Rider W, and resolutely confronted the Sonosaki family. What is the purpose of the Sonosaki family? What is the mysterious past of Kamen Rider W and Philip? Containing many mysteries, the battle of Kamen Rider W begins...