Elly is an expert in stalking - an academic at Cambridge University and a popular media pundit. She knows the subject intimately: what motivates a stalker how they behave how to rehabilitate them. But now it's personal. Someone is following her making silent phone calls and sending her ominous notes. The message is always the same - me or you. Elly can't trust anyone - not her family her friends or her colleagues. She knows that her stalker must be someone close to her. And when they suddenly turn violent she realizes she's running out of time to find out who it is. Because it looks like only one of them will survive.