DI Carter is put in a safe house after an arch enemy, Mark Dixon, is released from a psychiatric unit intent on revenge, convinced that Carter set him up. Dixon, a vicious rapist and murderer Carter put away some years ago, has already killed Carter's old sergeant. Meanwhile, Pcs Green and Law are assigned an undercover operation to find a local bootlegger.

Pc Pete Redfern is having a rough couple of days. Nobody attends his police Q & A session on the Carcroft Estate, he's splattered with ‘water' bombs and then he's suspended for clipping a ‘lippy' boy around the ear. Then local lad Euan (one of the bombers) goes missing, but the Christmas Street cops don't get involved until late in the day – perhaps too late. Suspended Pc Pete Redfern's knowledge is sorely missed when the police try to find him.

The gang is called in to break up a bare-knuckle fight but, in the ensuing fracas, an old woman collapses and dies. When her body goes missing, the team pursues a modern artist who wants to use a corpse in his latest masterpiece.

Two young burglars break into DI Carter's house and steal his illegally held replica Colt 45 pistol, leaving everyone involved in hot water. Meanwhile, Colin is drawn into a couple's kinky fantasies while on a surveillance operation.

Alfie Stokes is a sadistic, underworld-type who now claims to have found God, and he's DI Carter's star witness in the prosecution of Barry Roberts, a local drug dealer. But then former sergeant Yvonne Mackey turns up with some difficult question… Back at Christmas Street, Nick is livid that Sgt Dobson forgot to enter him for his sergeant's exams and threatens to take action.

Carter's confidence is shaken to its core when he pushes his luck too far. Miller finds herself having to go beyond the bounds of duty when she tries to stop two brothers dealing in stolen videos. A girl tries to have her dad arrested to end his life of crime – but her plan has tragic consequences.

Pc Clive goes in for some heroics involving one of Mulholland's tenants, and DI Carter goes after the gangster. But will Mulholland fall? Andy offers to work off his debt to dodgy landlord Mulholland – but ends up having to set fire to a house.

After a bungled drugs bust, DI Carter is left to salvage something from the few scraps he has. Carter and the team were after ambitious small-time dealer Gerald Ridley but chances of them getting him now look slight. Later, Pcs Green and Lawtry go to help social services take two children into care. However, it turns out they're ill-prepared and unequipped to deal with the mother and find themselves in the middle of a hostage situation.