The New Daughter (2009)

John James is a writer; his wife has left him. He moves with his two middle-school children to an isolated house off a dirt road in South Carolina. The property has an Indian burial mound, which fascinates his daughter, Louisa, who's entering puberty. Strange things: noises on the roof and in the woods, the cat missing, Luisa sleepwalking clutching a straw doll no one's seen before. She visits the mound often, staying late, coming home covered with mud. John's younger son, Sam, is frightened. John learns the house has a history and seeks out the previous owner. Louisa's behavior becomes more bizarre. Is there an explanation? An ant farm and a missing babysitter provide clues.