Eleven-year old Emily Alden is homeschooling by her fanatically religious mother Elizabeth, who doesn't allow her to interact with other people. But when Emily is visited by a mysterious girl outside her home, she rebels. Elizabeth warns Emily that the outside world is controlled by the devil, and attempts to correct her with prayer and study. When Emily is finally locked inside the house, she must decide whether to stay with her family or escape into an entirely unknown world.