Fuuto Tantei: Kamen Rider Skull no Shouzou

Fuuto PI: The Portrait of Kamen Rider Skull

"How were Gaia Memories created?" "Why did W begin to fight?" To answer Tokime's questions, Shoutarou quietly begins to tell a story. He speaks of his meeting and parting with a man he admired and called his old man—his mentor, Soukichi Narumi.

Mysterious people called Dopants, who utilized the powers of Gaia Memories, had begun appearing in the shadows of Fuuto, the City of Wind. A young Shoutarou had become an assistant of the detective Soukichi and, though yet half-baked, began to follow in his footsteps. Unaware that, in addition to his detective work, Soukichi was secretly acting as Skull, Shoutarou began to grow frustrated with his mentor. That was when the Narumi Detective Agency received a phone call—a request from Hell inviting Shoutarou and company to a fateful night! When Shoutarou tracked down Soukichi to deliver the "trump card" bestowed by the mysterious caller, what did he see?

Shoutarou and Philip. The night when Kamen Rider W and one detective made of two began. That whole story will finally be revealed.

(Source: Official site, translated)