From the outside it was just another middle-class London flatblock. But inside it a brooding, ages-old evil was stirring to horrifically malevolent new life, infecting the occupants with murderous, corrupt impulses - impulses that would lead to an escalating orgy of torture, mutilation and all-out slaughter, climaxing in the bloodiest, most bizarre confrontation with the forces of Evil Incarnate that the world had ever known.