When Melissa first notices the change in her husband - subtle at first - she thinks it may be the stress of moving into their new home. Or working long hours. But soon her husband turns into something far darker, far more sinister. Who or what is the dark shadow living beneath her husband? What is haunting him? Melissa must quickly find the answer to these questions, because Mark is changing, and fast. Soon her fight will be for her life, as well as for her marriage.