A teenage girl and her mom think Crestwick will be a great place for them to have a new beginning but little do they know, the house they are moving into has been plagued by an evil demon known as Nefas dating back into the 1800's. Nefas has fed on the souls of innocent young girls and now has a new target. In order to save this teenage girl and her mother, a skeptical, small town doctor is forced to confront his own demons before another girl suffers a gruesome fate in his family's old house. The film was inspired from real events from the 1870's and has been updated to give a fresh perspective on possession and the pure evil that Nefas has been known to bring.

Mona (Golshifteh Farahani), 26, an immigrant from North Africa, runs her in-laws' mini market in Chicago. She's married to Mourad, a man who can't stand up to his authoritarian mother. Mona is harassed by her mother-in-law because after five years of marriage, she hasn't been able to get pregnant, something that's considered a shame and a taboo in her culture. Marilyn (Sienna Miller), 29, is a receptionist at a computer repair company. Her marriage with Harvey is on the ropes. The only thing in her life that makes her happy is her belly dance class, a passion shared by Mona. Dancing at family gatherings lifts her spirits up and makes her forget the misery of her daily life. Marilyn shops at Mona's mini-market. They've become friends. One morning, Mona's mother-in-law is found dead in her bed. Mona realizes that she mixed the wrong dose while preparing her medicine. Realizing that she might be accused of murder, Mona runs away and flees Chicago by bus. Marilyn loses her job because of the recession. When she gets home, she finds out that her husband is cheating on her. With nothing left to lose, Mona decides to go to Santa Fe to enter a contest hoping to join a famous belly dance company. Mona and Marilyn run into each other on a rest area on the side of a highway. They decide to continue the trip together. They cross the USA, pitching their tent in trailer parks and in the middle of the desert. They earn some cash belly-dancing together in restaurants and bars. Back in Chicago, Mona is considered a fugitive; she's wanted for the murder of her mother-in-law. Harvey asks the police to look for Marilyn who disappeared without leaving a trace. Will Marilyn succeed in joining the belly dance company? How long will Mona be able to keep her secret from Marilyn? And how long will she be able to escape the law?