Build a movie plot around this: Who plays Elissa? Jennifer Lawrence
A young psychotic girl murders her parents with a hammer in the middle of a stormy night.Four years later, a newly divorced woman, medical doctor Sarah Cassidy (Elisabeth Shue), and her 17-year-old daughter Elissa (Jennifer Lawrence) move to a small, upscale town. Their house is near the house where the massacred family lived. As told by the neighbors, four years prior, a girl named Carrie-Ann Jacobson killed her parents, then fled into the forest and was never seen again, leaving her brother Ryan (Max Thieriot) as the sole survivor. Ryan now lives alone and is hated by his neighbors; Bill Weaver (Gil Bellows), a local police officer, appears to be Ryan's only supporter.The mother-daughter relationship becomes rocky and Elissa starts dating Ryan against her mother's wishes, finding Ryan to be lonely but a sweet boy. Ryan confides in her that he accidentally injured Carrie-Ann by allowing her to fall from a swing when they were little; he was supposed to be watching her while their parents were getting high on drugs. The resulting brain damage from the accident made her extremely aggressive, leading to their parents' murder. Ryan is revealed to have been secretly taking care of a seemingly now-grown Carrie-Ann (Eva Link) in a hidden room. When she, Ann, escapes, Ryan accidentally kills her while trying to hide her. In grief, he goes to the diner, where he meets a kind waitress named Peggy (Jordan Hayes).Later, some unruly high school boys pick a fight with Ryan and he flees, and Elissa drives to his house and subdues a fire the boys started. She finds tampons in the kitchen garbage and explores the house with suspicion until she finds the secret room and is attacked by Carrie-Ann, who is revealed to actually be Peggy. Ryan restrains "Carrie-Ann" while frantically screaming at Elissa to leave. Elissa finds blue contact lenses and Peggy Jones's wallet in the kitchen. Ryan has kidnapped the waitress and attempted to make her look like Carrie-Ann. When Elissa tries to leave, Ryan knocks her out by hitting her...