Dublin gang boss Nidge (Tom Vaughan-Lawlor) has been blooded and proved his mettle. He has killed his predecessor John Boy, he has killed his brother-in-arms Darren. He has shown he has the necessary ruthlessness to get to the top. He has killed friend and foe to become King - but the throne is a dark and lonely place. Series 4 begins with Nidge and the gang trying to survive in the endless recession that dogs the rotten Republic. Nidge has his hooks into a client who has fallen behind on his tab and sees an opportunity to extort him into helping to import a large consignment of drugs. But unknown to the gang their activities have attracted the attention of the police - in the form of a semi-autonomous squad of secret undercover operatives. It's headed by Detective Inspector Mick Moynihan (Brian F. O'Byrne) cool, steely, manipulative, he is determined to bring Nidge down, and his unit employs an array of complex surveillance, mind games and dirty tricks against his target. As an increasingly paranoid Nidge works to put together the deal of a lifetime, he's unaware Moynihan and his team are watching his every move..