When Mary and her teenage son, Fergal, move to yet another new home, it soon becomes clear they live their lives on the run, hiding from someone or something, terrified of being found. Their hunter Cathal (James Nesbitt) soon picks up the trail, intent on tracking and killing Mary and Fergal he will go to any length to succeed in his quest often using dark arts to aid him. Mary’s only defence is to use an ancient form of magic of her own to protect her only son. When local residents begin to be brutally murdered by an unknown life force, the sense of fear escalates. Is Cathal the beast responsible for the killings? Or is it the beast that he is trying to destroy?