Episode 4

S2 E4: While AC-12 are under increasing pressure to indentify the police leak that led to the ambush, Hastings (Adrian Dunbar), Steve (Martin Compston) and Kate (Vicky McClure) have their own demons to battle. Meanwhile, Lindsay insinuates that Deputy Chief Constable Dryden (Mark Bonnar) was embroiled in a wider conspiracy and when AC12 discover video recordings made by the witness while in protective custody, Dryden's guilt is compounded. Then Steve Arnott uncovers evidence that a tracker had been planted on one of the convoy vehicles and it seems that Lindsay (Keeley Hawes) has been telling the truth all along. When she is given special dispensation to visit her dying mother, AC12 realise too late how much danger she may be in.