After a police operation ends in catastrophe, DCI Eve West is suspended. She faces expulsion from the force, until John Duran - a violent criminal Eve incarcerated herself and who is still serving his sentence - offers to help clear her name. But nothing comes for free. Duran wants Eve to help free a fellow prisoner, who he claims has been wrongly convicted of murder. But as her investigation grows darker, Eve finds that more than just her job is at stake, and Duran is a dangerous man to trust . . .