Ruth Ware’s latest novel is set in an isolated mansion in Scotland. Rowan has just applied to be a nanny and travels from London for an interview. She has been working for low wages in a day care and is hoping this job will give her the boost she is looking for. She is hired and left on her own with the two youngest daughters on her second day there when the parents are called away on a business trip. She knows there is a chance the house is strange or haunted (!) as the mother indicated such in her advertisement for the post. Not only is the house creepy and weird things occurring immediately upon her arrival, but the architect parents have updated the house so it operates using the latest technology- the ‘Happy” app. All of the lights, HVAC, and refrigerator are controlled through this app. There are also cameras in every room. The novel starts ‘at the end’ as Rowan is writing from prison having been arrested for the murder of one of the children. “Turn of the Key” is pure creepy atmosphere with an unexpected twist at the last chapter.