Sarah (Taylor Schilling) is the mother of a young son Miles, whose disturbing behaviour signals that an evil, possibly supernatural force has overtaken him. Fearing for her family’s safety, Sarah must choose between her maternal instinct to love and protect Miles and a desperate need to investigate what – or who – is causing his dark turn. She is forced to look for answers in the past, taking the audience on a wild ride; one where the line between perception and reality becomes frighteningly blurry.