Season 3 of the award-winning crime drama starring Suranne Jones and Lesley Sharp returns with one case that rocks the Manchester police department across eight harrowing episodes. Will the strong bond hold between detectives and friends Janet Scott and Rachel Bailey? Just as their love lives fall apart, the mismatched but perfectly paired duo must face the toughest case of their careers.

Suranne Jones and Lesley Sharp return in this crime drama exploring the personal and professional lives of two detectives. This series sees both Rachel Bailey and Janet Scott in line for promotion but with only one sergeant's role up for grabs, they must compete against each other. Rachel's mum is back on the scene with a new boyfriend who Rachel discovers has a violent past. Janet has personal issues to deal with when her daughter decides to leave home. Rachel starts a new relationship, but because her lover is a senior police officer, she must keep it secret.

Upon stepping into the position of acting DI, Rachel senses the growing divide amongst her team. With Janet preoccupied by the arrest of her daughter and unable to advise on the situation, the two are left struggling to refocus on the horrific case at hand: the sinister world of Darknet. Offering complete anonymity to its users, a ruthless game is being played - one man challenges another to murder, leaving a chalk mark at the scene as proof. The images are loaded to a website and the baton is passed to the next killer. Will Janet and Rachel be able to stop these vicious killers before it's too late?