Rachel Bailey and Janet Scott are two detective constables working for DCI Gill Murray on the Manchester Metropolitan Police's Major Incident Team, tasked with tracking down killers. Bailey is intuitive, funny and passionate about her job. But her impulsiveness occasionally leads Murray to consider her to be a liability. Scott is reliable and a thinker. The mother of two is a very private person who is in a marriage that has become little more than a convenient arrangement for her and her husband, Adrian. As a result of her marital problems, Scott has become sexually involved with her immediate boss, DS Andy Roper. Bailey and Scott draw on each other's strengths to deal with extreme and horrific crimes. One of the show's co-creators, Diane Taylor, is a retired detective inspector from the Major Incident Team of the Greater Manchester Police Force.