Good Cop is a British police procedural television series first broadcast on BBC One and BBC One HD set in the city of Liverpool. The plot centres around an ordinary police constable whose life changes forever when his best friend and colleague is attacked in a savage ambush.

A bad day for constable Rocksavage begins with an encounter with his estranged girlfriend, Cassandra and his daughter Libby; a confrontation with a vicious thug, Noel Finch, in a cafe; and later his partner constable Andy Stockwell is fatally injured in a targeted attack by the same thug and his gang members. Rocksavage encounters Finch, and is forced by circumstances to shoot him.

Noel Finch is dead and PC Rocksavage receives phone calls from Finch's associate, Callum Rose who knows what he did, culminating in a blackmail demand for £100,000. Rose begins to follow Rocksavage discovering where his estranged girlfriend and current girlfriend live putting Rocksavage under pressure who agrees to pay all he can raise, £35,000. After torturing and murdering Rose, Rocksavage believes he can return to a normal life.

Rocksavage takes photos of Cassandra, his daughter Libby, and her new boyfriend. This causes him more grief compounded by reading the eulogy at Andy's funeral. Two possible witnesses to the murder of Callum Rose are interviewed but the evidence is inconclusive. One witness, Bradley Pearson, becomes involved in a domestic row leading to a siege concluded by Rocksavage's intervention. The Detectives bring in Jonjo Heinz identified by Rocksavage as a third gang member who attacked Andy but he is released through a lack of hard evidence. Rocksavage plants the murder weapon in Heinz's home.

Rocksavage recovers the gun, and breaks into Jonjo Heinz's house intending to kill him. However, before be can confront Heinz the police arrive to raid the property, forcing Rocksavage to flee. Heinz is arrested for Andy Stockwell's murder, but there is insufficient evidence to charge him, and he is instead charged with a drugs-related offence, but Rocksavage's knowledge of an arrest at which he wasn't officially present draws the suspicion of DCI Costello. Rocksavage meets Cassandra at the beach where he tells her he wants to be part of his daughter's life. Constable Amanda Morgan agrees to pose as a student to catch two men who have been attacking young women, but when the undercover operation goes wrong Rocksavage decides to take action. After Kyle Smart, his informant points him to the assailants Rocksavage shoots and kills one of the attackers, but inadvertly fires at Smart when he unexpectedly shows up at the scene. Racked with guilt Rocksavage walks into the sea, although his fate is left ambiguous.