A series of Gruesome killings is shaking Herefordshire. Beth, a mother in her sixties is showing signs of early Alzheimer. Worried about her, her daughter Jess and son in law Connor, try to find a way to help her. Together they purchase an old house on Wyvern Hill so that she can move in with them and be looked after. However, her symptoms and slow loss of reality render Beth unable to realize that something has moved in with her, observing her every move and preparing in the darkness of Wyvern Hill. 　　译文(3): 赫里福德郡发生了一系列骇人听闻的杀人事件。贝丝，一位60多岁的母亲，出现了早期阿尔茨海默病的迹象。由于担心她，她的女儿Jess和女婿Connor试图找到帮助她的方法。他们一起在威文山买了一栋老房子，这样她就可以和他们一起住并得到照顾。然而，她的症状和对现实的缓慢丧失使贝丝无法意识到有什么东西已经进入了她的体内，观察她的一举一动，并在威文山的黑暗中做准备。