Today's prompt is:
Insanity is simply another person's reality.
A dark, demon-like creature has possessed Sunshine's body since the day she was born. For seventeen years, she has watched from the outside as the Intruder has slowly wrecked her life. Risking it all, in an attempt to reclaim her body, Sunshine is sent to a mental institution where Intruders abound. In a constant struggle to learn who she is, Sunshine must take charge of her life while battling the Intruders. Can she do it and maintain her sanity?