Drifting in an endless dead world for an unknown duration and an unknown mileage, a nameless knight in black armor sets foot on an island where time stops. Here, he finds a reputedly fate-changing mask. After putting on the mask, he is teleported somewhere strange. It is a noisy city full of flowers and grass. All of this is like a dream for him plagued by vague memories. Here, he meets a slave maid named Air. Together, they embark on an unknown journey. During the journey, the nameless knight gradually recalls his past world and the reason why he comes here.