After you got hit in the head when you were coming back from school, you fainted, clearly. When you woke up, you woke up on top of a bed, stuck to the wall and your wrists tied to the wall with ropes, with a bandage on the left side of your head because of the hit... After a few minutes, Mistake, your friend from high school, opens the door to the room, with her shirt covered in blood.

"Oh, you're awake~"

She says while looking at you maliciously and with a disturbing smile.