The film begins with a teenage girl, Laurel Miller (Jessica Lowndes), going into the woods to meet her boyfriend Michael (Randy Wayne). He gives her an early birthday present, but her father (Jamie McShane) shows up and demands that she leave with him. As they drive home, Laurel tells him that she will be marrying Michael as soon as she turns eighteen. He breaks down and apologizes to her, telling her he can't let her turn 18, then purposely crashes their car. Seeing that she is not dead, he kills her with a broken piece of mirror, saying he couldn't let the darkness take her.
The film then switches to present day where 17-year-old Molly Hartley (Haley Bennett) is stabbed in the chest by her deranged mother Jane (Marin Hinkle) with a pair of scissors one day after school. Although she survives and her wound is healed with only a scar remaining, she is still haunted in her dreams and hears things because of the frightening experience. Molly lives with her father Robert (Jake Weber), and her mother is locked up in a mental ward outside the town she recently moved to. Her father enrolls Molly in a new school to help with the trauma and start a new life. However, as her eighteenth birthday approaches, Molly must deal with both the stress of being a new student and with the continuing nightmares she has of her mother's attack. Joseph Young (Chace Crawford), one of Molly's classmates, attempts to help her; however, Molly begins to display symptoms of the same psychosis that took control of her mother's life. Molly then attends a party at Joseph's house, where his jealous ex-girlfriend tries to attack her. She breaks her arm after leaving the party on foot, due to being refused a ride home by one of her new friends. Then she has another hallucination of Jane and has a panic attack. The next morning she apologizes to Joseph's ex, who tells Molly she knows that Molly is really asking what she is. After telling Joseph to leave her alone, Molly runs into Alexis (?), who offers salvation which Molly declines. Afterwards she arrives home where she is cornered by Jane and discovers that she, and others who share her mother's concerns, want to kill her in order to save her from a preordained life as a servant to Satan. It is revealed that Molly had died as the result of a miscarriage and her parents made a pact with the Devil disguised as a woman to save her life. The terms of the agreement were such that the Hartleys would only have Molly until her eighteenth birthday, then she would belong to the Devil. After Jane is accidentally killed, and upon knocking her father out, Molly runs to seek salvation by accepting a baptism by Alexis, who later tries to drown her after stating she know what she is. Then Alexis accidentally is knocked on her head which kills her and Molly turns to Joseph for help, only to discover that he is one of them and has set her up by taking her to his house.
Dr. Emerson (Nina Siemaszko) arrives at Joseph's house and tells Molly that she is also to be a servant of the devil. She says Molly can either kill her father to break the pact, or submit to the Devil. She tries to let her father live and avoid her fate by attempting suicide with a kitchen knife. This attempt is in vain because the clock has already struck midnight.
The film switches to a mental institution, where a doctor is talking to a woman dressed in black, later revealed to be a cold-hearted Molly. It is revealed that Molly's father has now been admitted to the institution; Molly casually smiles and says she will not speak to him, instead choosing to move on. Molly becomes valedictorian of her high school, and dates Joseph. She is seen leaving her high school graduation with Joseph in a limousine, after being told by Dr. Emerson (disguised as the school guidance counselor) that they'll "see her soon."
The Haunting of Molly Hartley opened theatrically on October 31, 2008 in 2,652 venues, earning $5,423,315 in its opening weekend, ranking number five and second among the weekend's new releases. The film ended its run on February 5, 2009, having grossed $13,559,812 in the domestic box office and $1,858,937 overseas for a worldwide total of $15,418,749. Based on an estimated $5 million budget, the film was a minor box office success.
The film was widely panned and currently holds a 28/100 rating on Metacritic, based on 10 reviews and a 3% "Rotten" score on Rotten Tomatoes, with the site's critical consensus being "The Haunting of Molly Hartley is a rather lifeless horror endeavor, with a pedestrian plot and few scares." Its best review came from the Toronto Star which said "If you get past the retro Nancy Drew title, this is a worthwhile effort." The LA Weekly wrote "From Freestyle Releasing, the self-service distributor that brought you D-War and In the Name of the King: A Dungeon Siege Tale, comes a movie even worse than those two combined."
Originally independently released by Freestyle Releasing, all ancillary rights reverted to 20th Century Fox upon its DVD release on February 24, 2009 via Fox's home video division, since Fox holds rights to release Freestyle films on DVD. The film was released in Mexico on June 4, 2010 via Quality Films. The UK DVD was released on June 14, 2010.
Although a formal soundtrack was never released, the following songs were used in the film:"Preparedness" by The Bird and the Bee
"I Don't Wanna" by Anna Waronker
"Rain" by Bishop Allen
"Post Man" by The Sammies
"17" by X-Press 2
"Falling Out" by The Sammies
"U a Freak (Nasty Girl)" by Chingy
"Mad Scientist" by Madison
"Untouched and Intact" by The Honorary Title
"Overwhelmed" by Keren DeBerg
A sequel, The Exorcism of Molly Hartley, was released direct-to-DVD on October 9, 2015. The film, directed by Steven R. Monroe, stars Sarah Lind as Molly with a supporting cast of Devon Sawa, Gina Holden, and Jon Cor.