The six-part series focuses on DS Nancy Devlin (Karla Crome), a detective with the National Crime Division, who is assigned to Brighton CID to investigate the murder of Frank Le Saux (Philip Glenister), a corrupt businessman with whom she has been associated in the past.

Having been present at the scene of the murder, Nancy struggles to keep her involvement in the case a secret, whilst working under the watchful eye of boss DCI Michelle Newman (Lindsey Coulson).

[2] One night, Frank Le Saux (Philip Glenister), a corrupt businessman, arranges to meet DS Nancy Devlin (Karla Crome), a National Crime Division detective who has been protecting him from prosecution on several occasions.

After the attempted murder of a customs agent the National Crime Division assign Nancy's fellow NCD detective Kevin O'Dowd (Rob James-Collier) to the case.

Nancy suspects that Gunner may be the leak, but during a late-night visit to O'Dowd's hotel room, she discovers a series of surveillance photos that disappeared earlier in the day.