What begins as a happy honeymoon for newlyweds Bea (Rose Leslie) and Paul (Harry Treadaway) takes a sinister turn when Bea disappears from bed one night and Paul discovers her the next day naked in the woods with no memory of how she got there. Soon Bea begins an escalating, unexplainable shift from a happy, carefree young woman to a cold, distant, and calculating one. Supernatural forces may be at work, but they uncannily echo some of the anxieties that come with a new marriage-issues such as secrecy, mistrust, and loss of identity.