James Nesbitt plays Detective Sergeant Tommy Murphy, a maverick cop with a dark past. After failing a psychiatric assessment, he is given one last chance by his boss and given a dangerous undercover assignment. Murphy is a loner with little to lose and deals with everything on his own terms...

Episodes Comprise:

The Goodbye Look: It's going to be a doddle. Posing as a criminal, Murphy has to sell a gun to a low-level low-life, and then nick him. In a single act of lunacy or inspiration, Murphy walks out of his world leaving behind the security of back up and surveillance. He's making it up as he goes along.

Disorganised Crime: Callard recommends Murphy's services to the McGeechans. They need some illegal assault rifles reactivated. Daniel and Gerard both have violent pasts and nasty tempers. Murphy is trapped. He needs to find out what they are planning. And he needs to stop it.

Strong Box: Dave Callard is after some moody money. If Murphy can turn supplier and Callard takes the bait, it's more evidence in the eventual charge sheet against him. If he makes one mistake his cover could be blown, along with the operation.

Extra Mile: Murphy needs to run the extra mile of this operation. This should have been over long ago, and he's starting to lose it. Rees, convinced he will uncover a criminal connection, is determined to pursue the relationship between Callard and Garvey. If he's right, this could be the biggest collar of his career. If he's wrong, he's putting his team through hell. And for nothing.

Boy's Night Out: Callard ups the stakes. He wants to meet Murphy. Urgently. Rees and Murphy suspect that it's an invitation to join Garvey's drug importation but Callard is being evasive. Murphy must smoke him out juggling his time to serve two masters: the Court and Callard's importunate demands.

Hard Boiled Eggs and Nuts: Murphy is holed up in hiding with Callard and Miller. The atmosphere is thick with menace. Callard systematically destroys the forensic evidence against him. Murphy and Miller fear that he may want to destroy one or other of them too. Or both. Murphy is outgunned and outnumbered.