LINE OF DUTY, SEASON 2 – Series (NR)--Following one multi-stranded investigation over five hours, Line of Duty sees Detective Sergeant Steve Arnott (Martin Compston) transferred to AC-12, an anti-corruption unit, after a mistaken shooting during a counter-terrorist operation. Alongside Detective Constable Kate Fleming (Vicki McClure), they are assigned to lead an investigation into the alleged corruption by a popular and successful officer, Detective Chief Inspector Tony Gate (Lennie James). While Gates cleverly manipulates his unit's figures, DS Arnott questions whether Gates is being made a scapegoat for a culture of institutionalized spin, or is guilty of darker corruption.