Arnhill sits staining the hills of Nottinghamshire. A rundown mining community which never properly survived the closing of its mines. Now it's haunted by a new tragedy after a boy is killed by his mother. But before she turned the gun on herself she used his blood to smear a chilling message on the wall. Not My Son. Shortly afterwards, Joseph Thorne returns to Arnhill but he is stalked by a sinister figure from the present and painful memories of the past. As Joseph takes over the dead woman's job and moves into her house, still stained with blood, he realises the secrets of his past still lurk in Arhill's shadows.