This manga is something of a side story to the Playstation game of the same name, though you don't have to have played the game to understand it. London, 1899: A girl with special powers runs away from the sanatorium, a hospital where she'd been kept. Her name is Koudelka, but that's all she remembers about herself. She meets up with a boy called Joshua, and together they flee from the agents of the sanatorium, who seem to be obsessed with her. Will Koudelka be able to escape from her pursuers, regain her memories, and discover the mystery that is her own power?