After seeing a man's head split open by an axe, 16-year-old Yuri Honjou trembles with fear and confusion as she flees from the masked attacker, only to discover she is trapped in an abandoned building where every door is mysteriously locked. Desperately looking for an exit, Yuri runs to the rooftop, but a lifeless world stands before her, surrounded by high-rise buildings. Though filled with despair, once she learns that her brother is also in this strange place, Yuri is determined to find him and escape. However, she soon finds that there are more masked murderers in the area, anxious to terrorize their newfound victims and satiate their sickest desires, leaving Yuri to question if they will be able to make it out alive.