Emily watson and denise gough star in itv's riveting cat and mouse psychological thriller, adapted from the novel by clara salaman. The three part drama focuses on the compelling and dangerous relationship between forensic psychiatrist dr emma robertson who is assigned to work with connie mortensen, a woman accused of a heinous crime but who claims she can't remember a thing. Dr robertson is not easily shocked. She's worked with her fair share of high security patients. However, when she's sent to assess connie for trial the two women become dangerously close. Connie has a searing insight into emma's deepest insecurities and starts to brutally exploit them. Their sessions become a complex psychological game with confusing undercurrents. As emma tries to uncover the truth and learn what triggered connie's despicable behaviour, it seems that her attempts to see justice done may destroy her instead.