When the ZQN zombie outbreak reaches Nagasaki, a withdrawn high school dropout named Yamada, who trusts no one and spends his time alone with his camera, is thrown together with Aya Nirei, the kyudo archery champion from his former school. Despite Yamada’s deep distrust of others, Aya declares her intention to be his hero and protect him as the undead plague rapidly consumes the city. Suffering from vivid hallucinations, Yamada dreams of escaping to the deserted Gunkanjima (Battleship Island) to find safety. Their fragile partnership forces them to navigate not only the swarms of infected, who retain deformed echoes of their former instincts, but also the sinister actions of a human survivor named Kagawa, who leads a group of refugees. The narrative arc follows this strange duo as they flee the collapsing streets of Nagasaki, confront their personal demons and mutual suspicions, and fight for survival against both the ZQN and the desperate, corrupted measures of other human beings in a final stand on the abandoned island.