Holly and Roz spend most of their days together. They like the same jokes, loathe the same people and tell each other everything. So when single mum Holly gets a shot at her dream job after putting everything on hold to raise her daughter, she assumes her friend will be dying to pop the champagne with her. But is she just imagining things, or is Roz not quite as happy for her as she should be? As Holly starts to take a closer look at Roz's life outside their friendship, she begins to discover a few things that don't add up. Who is the woman who claims to be her ally? Perhaps it was a mistake to tell Roz all her secrets. Because it takes two to forge a friendship. But it only takes one to wage a war...