Just as Fay Ryan is about to break the news to her husband Jack that they are to become parents, he gives her a gift intended for the mistress Fay knew nothing about – a mistress who is also Jack’s boss, Iona. Jack ends the affair, but odd things start to happen – complaints about Fay at work, a stolen item placed in her bag in a shop. It is only when Iona confronts Fay in person that they realize she has started a frightening campaign of harassment in her determination to win Jack back.