2 episodes

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5 episodes

DS Steve Arnott is transferred to the police anti-corruption unit after the death of a man in a mistaken shooting during a counter-terrorist operation by another cop.

6 episodes

An ambush of a police convoy results in three police officers dead and a protected witness seriously injured. The sole surviving police officer is Detective Inspector Lindsay Denton. Deputy Chief Constable Mike Dryden takes personal charge, assigning AC-12 to the case.

6 episodes

After a criminal is shot dead during a police raid, the AC-12 team begins examining the conduct of Sergeant Danny Waldron, leader of an elite unit. But Waldron’s loyal team obstructs the investigation, and the truth about the shooting proves more complicated than Arnott and Fleming could ever have imagined.

6 episodes

The fourth series sees AC-12 facing their most devious opponent yet! Under pressure from her superiors, DCI Roz Huntley charges a young man with a series of murders after months of fruitless investigation, but is he guilty? The Chief Forensic Investigator has doubts and turns to AC-12.

6 episodes

Series 5 follows the actions of Superintendent Ted Hastings, D.I. Kate Fleming and D.

7 episodes

Series 6 sees AC-12 facing their most enigmatic adversary so far: Detective Chief Inspector Joanne Davidson, the senior investigating officer of a high-profile unsolved murder.