In the bustling city of Fuuto, Shoutarou Hidari, a tough private eye working at the Narumi Detective Agency, teams up with his curious partner, Philip, to maintain peace and order. Their mission takes a thrilling turn when they cross paths with a mysterious woman named Tokime, linked to a string of crimes involving powerful 'Gaia Memories' that transform users into dangerous 'Dopants.' Tasked with eliminating these menacing threats to society, Shoutarou and Philip, also Gaia users fighting for justice, transform into the legendary Kamen Rider W. As they delve deeper into the case, they must not only battle the malevolent Dopants but also unravel Tokime's secrets and confront a shadowy past that refuses to stay buried.