The body of a young woman is found spinning inside the dryer in the laundry room of an upscale apartment building. When Castle and Beckett discover that the woman, in her 20s, worked as a Nanny in the building, their investigation leads them to a world of sex, lies and "playdates." Meanwhile, while writing the first novel to his "Nikki Heat" series, Castle delves into the thoughts and actions of Beckett, as she navigates the murder case while revealing more of her own mysteries.