We start off in the woods where we see a young woman walking through the woods following a trail marked by string. She gets a little nervous as she goes as she keeps hearing things. At the end of the trail is an old house. We are told that she is Laurel Hartley and its 1997. Once inside she looks around and is surprised by her boyfriend, who presents her with a heart shaped necklace (early birthday gift) Laurel’s father shows up to take her home and on they way they fight over Laurel and her boyfriend (she is about to turn 18 and wants to marry him) Her father keeps apologizing to her and puts his hand over a bible as he starts to drive out of control. A fast ride ensues and Laurel stops the vehicle, only for them to be struck by a semi. As they lay injured her father keeps telling her over and over he can’t let her turn 18. We don’t see her again.
Cut to the present where we see a young girl walking into a bathroom. She sees a woman on the floor praying (her mother) and she keeps begging Molly to pray with her, when she finally does, the woman raises a pair of scissors. As she goes to stab her, Molly wakes up. Over breakfast we learn Molly is starting at a new prep school and her mom is not around.
At school, Molly meets with the new principle and learns she will have an appointment with the counselor and her record is sealed. (We’re shown this) Molly is shown to her new classes by Alexis (a very religious girl there on scholarship) and meets Joseph Young and some of the other students. During lunch Molly begins to hear things (which happens a lot) and runs to the bathroom where she suffers a nosebleed. She starts hearing noises and begins to have a panic attack. It ends when a girl walks out of the stall saying she can't hide in there forever, she has tried. Molly ends up skipping her counselor session and walks around outside school. Joseph finds her and offers a ride but she turns him down.
At home over dinner, Molly’s is pretty morose. She and her father discuss their day and Molly worries whether or not her mom can get out. She excuses herself to go do homework. During the night she has another nightmare about her mom.
Later on, in another class the students are handed out bibles (they are reading Paradise Lost and the teacher wants them to better understand the story). Alexis who has her own bible with her argues with the teacher over using the bible as a text, during which Molly has another nosebleed and is excused. In the bathroom she has another attack and is found by Alexis who brings her a shirt.
Molly has a session with her counselor. Here we learn more about her moms’ condition and that Molly’s mother stabbed her. Molly isn’t really into the session and leaves, but not before the counselor gives her a card with her number. As she leaves we see the same girl that was in the bathroom waiting for her own session. (Leah) Later on in the Library, Joseph finds her reading about her moms mental state and offers her a ride again, which see accepts. As they are walking in the halls Molly’s dad shows and up and asks what’s wrong. Molly isn’t having it and walks outside where she finds a visitors pass for the hospital where her mom is kept.
Later that night as she is getting ready for bed, she hears the water running in the bathroom. She goes to turn it off and the door is suddenly shut and locked. She freaks out and calls for her dad’s help and neither one can open the door. She blacks out.
Molly wakes up in the hospital to be told that they found a tumor in her nasal cavity near her brain, which could explain her symptoms. Later on Alexis visits her, asking her if she has been saved and mentions a relative who is a nurse. She gives Molly a teen devotional bible, which Molly shoves in a drawer.
Back at school Joseph corners her and asks her to attend a party. After talking to her, Susie (Joseph's ex or not, you can't really tell) gives her hard time, till Leah butts in and breaks it up. Leah decides to join Molly at the party. Molly tells her dad she is going to a study group and might be home late. She is told to keep her phone on her. Leah picks her up and drives her during which Molly and Leah share their stories.
Once at the party they separate and Molly goes to hang and dance with Joseph. As he leaves to deal with a problem, Susie picks a fight with Molly, which ends with Molly breaking her arm. Since Leah won’t leave the party and drive her home, Molly hops the gate and walks home. Since she is having trouble with her cell, she calls her dad from a payphone, Molly then sees her Mom who keeps telling her she knows what she is. Molly runs from her only to see her disappear. Molly’s dad arrives to pick her up and take her home.
Later on Molly tries to apologize to Susie but she wont accept it, with her telling Molly she knows who she is (this is repeated a lot). Joseph tries to find out what’s wrong but Molly runs off.
At home she calls her dad and tries to relax. Lo and behold her mom shows up again this time with a blade. She tells Molly that she died the day she was born and that someone came forth and offered to bring her back. Having lost children before, her parents agreed on the condition that Molly belonged to them once she turned 18 (I'm assuming Satan). They fight through the house and in defense Molly shoves her off and her mom is thrown over the stairs to her death. Her dad arrives and tries to tell Molly what her mom said isn’t true. Molly hits him over the head and runs off.
She ends up at a Christian center where Alexis works. Molly begs Alexis for help saying she doesn’t have much time left (She turns 18 the next day). Alexis takes her to a church to be baptized. During the baptism, Alexis tells her that a relative told her Molly’s story and she tries to drown her. In the struggle Alexis hits her head and drowns. Leah shows up looking for Molly and gives her dad a gift. Molly runs off and runs into Joseph who offers to take her away. At his house while wafting, Molly tries to call her counselor but can’t reach her. She goes inside and finds Joseph waiting with a birthday cake and a knife. Molly keeps begging to leave and her counselor shows up saying she didn’t get the message. We find out that the counselor is the one who offered Molly’s parents the deal and that soon Molly will have great power and that she is the one. Molly doesn’t want it and her dad is brought in. Molly is handed the knife and given a chance to kill her father for the deal they made. As the clock strikes midnight, Molly stabs herself, but because she didn’t do it before the chimes finished tolling, she is spared.
We then see Molly at a mental hospital talking to a doctor about her dad’s condition. Molly doesn’t want anything to do with him. At her graduation she is gives a valedictorian speech and leaves with Joseph in a car, as the counselor wishes her good luck.