The Housemaid’s Secret by Freida McFadden (The Housemaid #2):

“Don’t go in the guest bedroom.” A shadow falls on Douglas Garrick’s face as he touches the door with his fingertips. “My wife… she’s very ill.” As he continues showing me their incredible penthouse apartment, I have a terrible feeling about the woman behind closed doors. But I can’t risk losing this job—not if I want to keep my darkest secret safe…

It’s hard to find an employer who doesn’t ask too many questions about my past. So I thank my lucky stars that the Garricks miraculously give me a job, cleaning their stunning penthouse with views across the city and preparing fancy meals in their shiny kitchen. I can work here for a while, stay quiet until I get what I want.

It’s almost perfect. But I still haven’t met Mrs Garrick, or seen inside the guest bedroom. I’m sure I hear her crying. I notice spots of blood around the neck of her white nightgowns when I’m doing laundry. And one day I can’t help but knock on the door. When it gently swings open, what I see inside changes everything…

That’s when I make a promise. After all, I’ve done this before. I can protect Mrs Garrick while keeping my own secrets locked up safe.

Douglas Garrick has done wrong. He is going to pay. It’s simply a question of how far I’m willing to go…