When DCI Roz Huntley captures a serial killer as part of a career-defining case in Operation Trapdoor, Forensic Coordinator Tim Ifield alerts AC-12 to a possible miscarriage of justice.

Under intense pressure to catch the culprit and prove herself to her superiors, it’s not long before AC-12 decide to probe her handling of the investigation. A mother of two and wife to husband Nick, played by our fab Lee Ingleby, Roz will do anything to stop her life unravelling.

Determined to uncover the truth, DS Steve Arnott, DS Kate Fleming and Superintendent Ted Hastings must work together to tackle their most devious opponent yet…

“Line of Duty” starts on Sunday 26th March, 9pm, BBC1