Eve wanders through the Tower of Babel, a dungeon that has appeared in the world. She realizes that she is in a cycle of being killed and resurrected by her challengers each time.
She meets Zero, the only person who hasn't attacked her, and agrees to accompany him to the tower's 10th floor to escape the cursed tower. Along the way, Eve realizes that she is not a real human being. She also discovers that the world she lives in is inside a virtual reality RPG game and that she is an NPC in the game...