Craving connection with others, Nancy (Andrea Riseborough) creates elaborate pseudonyms on the internet. When she meets a couple, Leo (Steve Buscemi) and Ellen (J. Smith Cameron) whose daughter went missing thirty years ago, fact and fiction begin to blur in Nancy's mind. As their bond deepens she becomes increasingly convinced these strangers are her real parents and reasonable doubts give way to wilful belief until the power of emotion threatens to overcome all rationality.