The Haunting of Molly Hartley.

When teenage Molly Hartley moves to a new town, she's haunted by terrifying visions that may have to do with dark secrets from her past. Something evil lurks just beneath the lush surfaces of her private-school world, and it holds the rights to her very soul. On the eve of her 18th birthday, Molly is about to discover the truth of just who or what she is destined to become.