5 episodes · 2012

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 · 2014

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. Initially AC-12’s most valuable witness, the suspicion soon arises that Denton could be their prime suspect. In the pursuit of corruption, how far will they go to uncover the truth?