Commander Clare Blake has risen to the top of her profession in the male-dominated Metropolitan Police Service, and is now the head of the serious crimes unit. Some years previously, she arrested James Lampton (Hugh Bonneville) for the murder of his beloved girlfriend. He was subsequently sentenced to life imprisonment, but has since been released on parole and has now become a successful author with a best-selling book based on his time in prison. Blake believes that Lampton is a reformed character, and begins to warm to his charms. However, Blake's colleagues, especially DCI Mike Hedges, believe that Lampton is responsible for another murder - and set out to prove his guilt