Answering questions from his amnesiac partner Tokime, detective Shoutarou Hidari looks back on how he first met Soukichi Narumi, the boss who took him in in the windy city of Fuuto and secretly moonlighted as Kamen Rider Skull. Set before the events of Fuuto Tantei, the film follows young Shoutarou's rocky start as Narumi's assistant while Gaia Memory-powered Dopants begin turning up around the city. It's the first animated feature in the Kamen Rider franchise.