A young girl buys an antique box at a yard sale, unaware that inside the collectible lives a malicious ancient spirit. The girl's father teams with his ex-wife to find a way to end the curse upon their child.

Movie Plot:

In the 1970s, a woman tries to open a strange box, attempting to protect herself with holy water and a hammer. She starts being thrown violently around the room and having seizures. When her son enters, she is unconscious on the floor.
In the present day, parents Clyde (Jeffrey Dean Morgan) and Stephanie Brenek (Kyra Sedgwick) are in the process of divorce, which is having an effect on their children, Em (Natasha Calis), and Hannah, (Madison Davenport). When the children move into Clyde's new house, they take time to adjust to the new split in their lives.
The next day, they stop by at a yard sale, initially to buy more dishes, but then Em becomes intrigued by an old box which has Hebrew inscriptions engraved on it. The box fascinates Em, but Clyde cannot speak to her much thanks to his ongoing job at the local university, which takes up most of his spare time. Em becomes solitary and spends all her spare time staring at the box. Em's behaviour increasingly grows more sinister, with Clyde and Hannah freaking out when they see her sitting in her room surrounded by moths one night. They hear an animalistic noise in their kitchen one night, but when the intruder escapes through their dog flap, Clyde assumes it was a racoon. Stephanie, Clyde's divorced wife, spends much more time with her new boyfriend, Brett (Grant Show), rather than with her original family, and Stephanie assumes the crowd of moths which were with Em were attracted to the pizza they had for dinner. Em's behaviour gradually grows more violent, and Clyde picks up on the change, but when she strikes out at a schoolmate who was trying to steal her box, she is brought to the attention of the authorities, who reccommend that she spend an amount of time away from the box which has fixated her so greatly. Unfortunately, the female psychiatrist assigned to look after the box that night dies when a malevolent force inside the box throws her rapidly around the room and beats her to death before throwing her out the window.
In a diner, Em tells Clyde about a woman who lives in her box and says she's "special." Em has notably changed by rapidly eating at a faster-than-normal rate. Em also tells Clyde that "she's still hungry." Clyde attempts to dispose of the box by throwing it in a garbage unit, but Em races from her house late at night and retrieves the box. Clyde is immensely disturbed and takes the box to one professor at the university he teaches gym at, and the professor tells him the box dates back to the 1820s and was used to contain an ancient Jewish evil, a demon named a Dybbuk (voice of Ella Wade). When the demon got too much to handle, the Jews contained it in a box, and sealed the box to prevent anyone opening it. Clyde immediately travels to the local Hasidic community, and learns from a Jew named Tzadok (Matisyahu) that the possession has three main stages, with the third stage being the one where the Dybbuk latches onto the host, becoming one entity with the host. The only way to defeat the Dybbuk is to lock it back into the box in a forced ritual, for which the demon's name is needed. Tzadok breaks the glass from the mirror inside the box and discovers it is named Abizo. At home, Em violently attacks her mother, Stephanie, when Stephanie discovers her eating raw hamburgers, but then the Dybbuk launches itself out of Em and tries to personally kill Stephanie on its own, but reattaches itself to Em, when the attempt fails. Em has no recollection of her violent attack. Stephanie reunites with Clyde to have an MRI scan on Em, Stephanie is horrified when she sees the Dybbuk's face inside her skeleton, near the heart.