The story takes place in a bizarre, isolated insane asylum.
The heroine, Maria, wakes up in a hospital room with no memory, only remembering that she has a daughter. The number '43' is carved into her wrist. The entire hospital is eerily silent, and both the nurses and patients seem like soulless puppets.
Soon, night falls and the hospital instantly turns into hell—all the people become crazed, bloodthirsty zombies chasing Maria. Just as she's about to die, a mysterious man named Ethan appears and saves her. Ethan seems to know everything about the place and keeps urging Maria: 'We must escape before 6 a.m.' But Maria can't understand him at all.
As time goes on, Maria gradually discovers that the asylum has a very strange cycle: during the day, everything returns to normal, and the staff are calm and gentle; at night, the whole hospital turns into a bloody nightmare. Even more terrifying is that Maria seems to have experienced all of this before.
She starts searching for her daughter, Lily, inside the hospital and slowly uncovers some horrifying truths:
- There’s a secret experimental area deep within the hospital;
- There are numerous human bodies that look exactly like her;
- Maria gradually realizes that she might just be a 'replica' in some experiment, or a human sample constantly being reset. And what she thinks of as her 'memories' might just be fragments left behind.
