When PJ's old nemesis Luke Darcy (see season 4's ""The Civil Dead"") is freed from jail, he returns to Mount Thomas and PJ instantly believes he is bad news.
PJ refuses to explain how he came to be standing over the dead body of Luke Darcy, forcing the Homicide Squad to arrest him for murder. The other Heelers must prove his innocence and find the real killer.
Rivalry runs rampant between Chris and her opponent in the lead up to council elections.
Ben faces a dilemma when he and his fiancée Marissa search for two homeless kids - the children of an itinerant drifter who collapsed during a pub brawl. Ben has already begun to suspect that he has met his match in selfless self-sacrifice in Marissa, but relations are strained when Ben realises that Marissa is hiding the kids.
When Susie finds herself escorting a pet alpaca to a funeral, she really begins to understand something about country policing. Unfortunately the recently acquired alpaca is the heir to a fortune, and suddenly all sorts of contenders emerge to make counter claims.
Ben and Susie face the inquest into Brad's death. What is hoped to be a mere formality quickly becomes complicated when a witness makes damning claims against them both - including accusations that Ben and Susie were having a passionate affair.
P.J. and Jo run into a wall of silence when they investigate the allegation that a music teacher employed by the Mt Thomas Brass Band has been having sex with his under age charges. Tom seeks help from his parish priest, who finds himself constrained by a skeleton in his own closet.
Tom has a black eye, PJ and Jo are in a foul temper after a bush walk goes wrong, Ben and Susie are frustrated after they chase a non-crime, and only when Jonesy reveals his adventures with a new Constable in Widgeree does PJ realise that they all hold a piece of the puzzle which may lead to the recovery of a quarter of a million dollars in stolen loot.
Susie and Evan find a young boy near death during a spate of alcohol robberies at the Imperial. Chris injures herself when she chases after the robbers, and Jones, feeling responsible for not coming to her aid when he had the chance, hires another bartender. But is he part of a gang who is forcing alcohol onto the young?
A woman who works out at the same gym as Susie and Jo is raped, and the Heelers suspect the gym owner when a witness cites sexual harassment. When looking through the local Internet sites, Jonesy discovers a porn site that includes the gym rape victims, and to her horror Jo as well. The race is on to find the rapist before Jo becomes his next victim.
On their way to see the new constable who took over the station in Widgeree, Jo and PJ become embroiled in a case that involves aliens, Ned Kelly's saddle and a missing boy. They struggle to find out the truth when even the local police believe they had been abducted.
Tempers flare as a man the town is convinced killed his son returns when the courts find him not guilty. Jo and PJ keep an eye on the lynch mob at the Imperial while Susie, Jonesy and Tom keep the man at the station. Infuriated with the court's decision, Jones schemes of a way to bait the man into attacking him. But he is not the only one who is seeking to take the law into his own hands, as justice is demanded at the Imperial when Chris is held at gunpoint.
The Heelers are called to the local women's prison after a number of attempts had been made to break in, including a young boy who wants to see his mother. When a digital camera is found inside, the prison warden and director come under suspicion for hiring out the detainees for illicit purposes.
Jo reopens the case of a missing teenager when his mother claims to have seen him in the dead of the night. Jo senses that there is more to the case than she imagined, and soon finds herself involved in a web of lies.
A former AFL player for the Hawthorn Hawks is robbed, and takes an instant liking to Susie when he goes in to report the robbery. Jealous, Evan investigates hoping to prove the former football hero isn't as innocent as he claims.
Susie and Evan make the horrifying discovery of about 50 dead kangaroos, looking to have been ripped apart with an automatic rifle. As debates rage over whether or not to thin out kangaroo numbers, the farmer who owns the land where the dead roos were found comes under suspicion. He denies it and suggests a mate he served with in Vietnam might be responsible for it, thinking that slaughtering the kangaroos might send a message to not have a cull. As the Heelers dig deeper, it is discovered that a cache of weapons from Vietnam had been kept, but when they come to seize them, some turn up missing. Now the race is on to find the weapons and whoever might be holding them.
Jonesy and Susie head to the site of an ecstasy overdose only to discover Jonesy's young brother Dylan, with the Drug Squad, got there first. Dylan loves to snub his brother because of their positions and soon leads an investigation into drugs in Mt. Thomas without listening to Jonesy's evidence. Jones goes after a brother and sister pair who he suspects, even though they are Dylan's friends, and his vigilance has even Susie convinced that he is just doing it to beat his brother. Meanwhile, a surprise 30th birthday party for Jonesy comes to a head when he fights with his brother, and they are seen fighting by Tom and Commander Jones - the boys' father. Later, Dylan collapses on the dance floor...
Dylan dies of an ecstasy overdose, after convincing his father that he doesn't take drugs, and it was Jonesy's fault. Susie enlists PJ's help to see whether it was Dylan's friends or his colleague who spiked his drink. Although Jonesy tries to keep his family name clean, his father soon suspects him of being on drugs and Inspector Monica Draper arrives to investigate. So when Jonesy finds evidence that his brother himself was on drugs, he is torn as to whether he should take the fall, or reveal what his late brother was really like.
A middle aged doctor is murdered on the morning he is supposed to give testimony and Jo - having her own personal dilemmas because she fears that she has fallen pregnant to PJ - is emotionally thrown by the case. When she withholds vital information, however, Susie starts to worry.
A bungled police raid leaves Ben shot in the arm by Susie and a formal investigation looks set to find her guilty of shooting him out of payback for her husband's death last year rather than an accident, even though the Heelers are sure that she is innocent.
It seems a usual day at the office: Tom's fishing trip is yet again interrupted by Grace's job, PJ and Jo have decided that its time to tie the knot, and the usual slew of cases are coming in the door.
After an old lady is mugged, tension builds in Mt. Thomas. Thanks to Clancy, an eye-witness of the event, suspicion rests on a new family in town: the Baxters. The adult children, Matt, Troy and Tarni are brought in but nothing can be proven. Their father Barry, a softly controlling man, comes to bail them out and shortly afterward, Clancy is bashed.
It is the day after the explosion. The Mt. Thomas police station lies in ruins; Senior Constable Joanna Parish is dead, as is Clancy Freeman; and Grace Croydon is missing. While Tom recovers in hospital, PJ, Ben, Susie and Jonesy move into the new police premises where they are met with a surprise: Nick Schultz, now a Detective Sergeant in Homicide, has arrived to investigate the attack. And he's not the only one.
Troy Baxter has been crushed underneath a car at his property. Barry blames Tom and, while most of the cops brush this off as grief, Nick thinks it may be true. As Jonesy, Ben and Susie move things in to the new station, PJ and Nick focus on Cal Millic, who Tom thinks is just a distraction. Probationary Constable Kelly O'Rourke arrives. She's fresh from the Academy, ambitious and enthusiastic, and determined to prove her worth. Her father, who was an old friend of Tom's, died in the course of his duty as a policeman. However, her attempts to convey her sympathy to Tom end in him disciplining her. She is quickly aware that Tom Croydon is a changed man.
Barry Baxter is on assault charges against Tom, and Chris is angry because she was forced to lie for Tom. She confronts him and then tells Susie that Tom needs help.
Tension is rife in Mt. Thomas. Joss and Kelly interrupt a girl who goes crazy in a store, and later find out that bad speed is being sold in the town. PJ and Nick are on bad terms over what they think of Tom's intentions, and Amy is just trying to get someone to let her help. Ben and Susie are acting professionally around each other, and Jonesy is annoyed about their dalliance.
The gruelling investigation of the attacks on the Mt. Thomas police continues, as Tom heads to Melbourne to investigate the man who sold the parts for the bomb. He links it to chemical dealer 'Doc' Parkinson, and is determined to prove that he provided the Baxters with supplies for both the bomb and the speed.
Despite allegations by her ex-boyfriend Theo that she isn't all she appears to be, Jonesy stays firm to Donna in trying to protect her. She soon moves in with him.
Jonesy finds his career on the line as he attempts to protect Donna, and so he is stunned when he learns that she is a call girl. When they are attacked by Theo, and Jonesy claims that Donna was abducted, Amy soon doubts his theory - thinking that Donna faked her abduction. Susie soon joins in on this theory, after Donna tells her that she has Jonesy now, and Susie can never have him back.
Jonesy is stunned when Donna tells him that the people who hired Theo to kill Hugo Allen were in fact the police of St. David's. As he goes about investigating secretly, he learns that the police have not been caring about Allen's disappearance. When Amy finds out about his investigation, he is forced to get Donna to talk to her.