Claudia seems to have the perfect life. Heavily pregnant with a much-wanted first baby, she has a ready-made family in the form of two small step-sons, a loving husband and a beautiful home. But she is also committed to her full-time job as a social worker. So when Zoe arrives to help her, it seems like the answer to a prayer. Except that, despite Zoe's recommendations as a nanny, there's something about her that Claudia does not trust. And when she finds Zoe in her bedroom, going through her clothes and reading her papers, Claudia's initial anxiety turns to fear. Meanwhile, vicious attacks on pregnant women are taking place, and Claudia becomes acutely aware of just how vulnerable she is...