Harriet Walker is a cop. She has it all, a loving husband and a promising career as a detective. But things go awry when her husband Matt, an undercover federal agent, is murdered. Within 24 hours, she has gone from detective to prime suspect and sets about burying her grief in her own private investigation. The painful search for details of her husband's death also leads to her confronting evidence of his infidelity. Together with new partner Joe, she must find her husband's lover to get to the truth behind the murder.

Harriet Walker is a cop. She has it all, a loving husband and a promising career as a detective. But things go awry when her husband Matt, an undercover federal agent, is murdered. Within 24 hours, she has gone from detective to prime suspect and sets about burying her grief in her own private investigation. The painful search for details of her husband's death also leads to her confronting evidence of his infidelity. Together with new partner Joe, she must find her husband's lover to get to the truth behind the murder.

While testifying in the trial of high-profile criminal Nick Hammer, Sophie is humiliated on the witness stand by an aggressive defence lawyer who calls her credibility into question. The case is lost and Joe gets into a heated argument with lawyer, Ray Jarvis, outside of court. Ray files an official complaint against Joe and Internal Affairs is called in to investigate the incident. Harriet won't lie to help Joe out of trouble. Her reluctance to help Joe may be warranted as Ray is soon found beaten in his home, claiming on TV for all to see that Detective Joe Hill was responsible for the attack. Joe readily admits he paid Ray a visit but that Ray refused to see him. It now falls on Joe's colleagues to not only prove his innocence, but to rebuild their original case against Nick Hammer and bring him to justice.

The Kingsway detectives are called in when the body of a young woman is found caught in a weir in a national park. It is learned the woman, a primary school teacher, was involved with a group of swingers, leading detectives to suspect the involvement of someone from within the group. The reported disappearance of another woman becomes a key element in allowing Joe and Harriet to solve the case. Despite his persistence, Sophie avoids Theo's overtures as she continues to keep details of her private life just that.

Joe and Harriet head up the investigation of a young model's death after her naked body is found in a city dump. Harriet quickly runs afoul of the dead woman's parents who are resentful of the modelling industry which they blame for their daughter's death. Complicating matters is the involvement of two of the office's staff members with the investigation: photos of Nicole, a former model herself, appear in the portfolio of a photographer under suspicion, and Theo is seen on a surveillance video chatting up the young model in a club just hours before her death. On the home front, Joe is having reservations about having Nicole move in with him while Harriet revives a longstanding disagreement with her mother when she challenges her over her dislike of police officers.

The discovery of a blood-soaked four-year-old girl walking alone on the roadside leads detectives Hill and Walker to the scene of a bloody massacre that has left an entire family dead, save the young girl and her injured father. The investigation is particularly hard on Harriet as it takes her back to the recent murder of her husband Matt. To make matters worse, she has learned, second hand, that the DPP has consented to drop the murder charge against the woman accused of the crime in exchange for a guilty plead to the lesser charge of manslaughter. On the verge of a breakdown, Harriet must stay focused as she and her colleagues work to locate a killer.

The body of a popular local swimming coach is pulled from a pool and the Kingsway detectives are called upon to investigate the murder. The coach, Jimmy O'Sullivan, was a life-long friend of Ted Hudson and rumours of his possibly being a paedophile do not sit well with the Senior Sergeant. Theo offers his support to Sophie, who is feeling hard-done-by, however an intimate moment between the two is interrupted by her four-year-old son. Back at work, Theo is forced to reveal Sophie's secret to Hudson who, as she feared, quickly reassigns her to a sexual assault case before finally suggesting she stick to desk duty for the time being.

The pursuit of a stolen car ends tragically when a police officer is killed after an iron bar is thrown from an overpass, smashing through the car's windscreen and piercing the driver's chest. The officer, Albie Borich, is an estranged friend of Theo, who must break the news to Albie's wife, who is pregnant with what Theo believes could be his child. The investigation of the case is difficult for Theo who roughs up Lenny Hunter, a man suspected of being the driver of the stolen car. Police suspect the accident may have been an ambush, targeting the policeman responsible for arresting Lenny's brother, but is all what it seems?

The Kingsway detectives are called in when an eleven-year-old girl is abducted from outside her school and held for ransom. The family's recent lottery win would appear to explain why their daughter was targeted but the detectives' suspicions also fall on the mother. The father's argumentative behaviour doesn't help matters and threatens to derail the detectives' hopes for an uncomplicated exchange of money for the girl's safe return. Joe takes the case personally and takes it upon himself to find the culprit, but his deep involvement begins to affect both his family and his relationship with Nicole who is still uncertain of where she stands.

An old unsolved case that has dogged Joe for nine years is reopened when a young woman is drugged and assaulted at a local beach. The attack is carried out in much the same manner as the murders of two teenage girls nine years earlier, one of whom's necklace the new victim is inexplicably wearing. The suspect in those crimes avoided prosecution due to insufficient evidence but Joe is quick to tie in the new attack with the unsolved crimes and begins building a case against him. Tension mounts when evidence links the suspect to a missing person case, the latest victim falls prey to a suspicious accident that could prevent her testimony, and the investigation is hampered by mistakes that could destroy the case before it's even built. With the investigation unraveling, Nicole, whose ambitions to enroll in the Police Acadamy are in jeopardy thanks to an incident from her past, volunteers to go undercover, placing her life at risk to obtain a confession and ensure the killer's conviction.

An elderly man is found dead in his home. His body is bound to a chair, his home has been ransacked, and a mysterious hole has been dug in his backyard. The Kingsway detectives are called in. Further complicating matters is a mysterious phone call placed from the man's home to the Kingsway station on the day the incident occurred. Joe believes the call was from a careless police officer phoning in the crime, but the call appears in Nicole's phone log having been dismissed as just one of a series of prank calls made to the station in recent days. It's a puzzling case with few suspects and no apparent motive, the detectives have their work cut out for them. Nicole reaches her limit with Joe. His inability to appreciate the guilt she feels at possibly playing a role in the man's death (as a result of not acting on the phone call) sparks her decision to move out of Joe's house. A controversial court decision by Harriet's mother affects Harriet's relationship with Sophie.

A suspicious death on an Army base brings out Harriet and Joe to investigate. The death would appear to be a suicide but Joe is not sure, suspecting the military of closing ranks to protect one of their own.

High-stakes gambler Eddie Campbell is found dead at the foot of the stairs in his home, the apparent victim of a burglary gone wrong. Eddie had recently won a large amount of money at the track, leading detectives in the direction of his associates in the gambling world. Joe meanwhile, beginning to feel the loss of Nicole from his personal life, becomes involved with Eddie's attractive niece, the sole heir to Eddie's fortune. Eddie's girlfriend, a former working girl, tries to stake her claim to a portion of Eddie's wealth as police find her at his house packing up his silver. With Eddie's $100,000 in winnings still missing and a series of possible suspects, it is a recording of Eddie's last phone call that provides the clue to his killer's identity.

The investigation surrounding the violent stabbing death of a pizza delivery boy takes an unexpected turn when the suspect brought in for questioning is found to be Ted Hudson's son Daniel, a paranoid schizophrenic.Daniel has been living on the streets off and on and has gone off his medication. There is physical evidence placing his at the crime scene and in questioning, he admits his guilt. It's a difficult situation for Ted as the secrets in his personal life begin to be exposed, including the breakdown of his marriage.

The body of Zoe Creek, a young waitress, is uncovered on the beach a short distance from where she worked. The woman's devoted fiancé tells detectives he suspected she was seeing someone else. His suspicions appear to be confirmed when it is discovered he is not the biological father of his fiancé's baby. With this revelation, attentions shift to real father, a married man who reluctantly reveals he had been approached by Zoe for financial assistance and met with her the night she was killed. Two troublesome young men enter into the mix as well. Joe is sure they're guilty of something but his heavy-handed approach results in little apart from a formal complaint being filed against Harriet. Theo presses Sophie for information about Eliot's father.

Theo and Nicole's evening out ends with an unexpected tragedy when Nicole is shot and rushed to hospital. With no reason for her to be the target of a contract-style shooting, the investigation is slow to develop. It is the discovery of a dead body at the bottom of a cliff that provides the crucial lead. The dead man, Lance Stiffner, was shot by the same type of gun that shot Nicole. It quickly becomes clear that Nicole was the victim of mistaken identity. The intended target was Nina Napolitano, who was having an affair with Stiffner. Her imprisoned husband found out and put out a hit on both her and Stiffner. The identity of the shooter is provided by a reluctant accomplice, and Joe and Theo are soon involved in a high-speed chase with their suspect. The chase ends when Joe draws his gun and shoots the suspect, believing to be in danger of being shot himself. However, upon searching the car, no gun is found. Was Joe mistaken or was it a case of cold-blooded revenge?

The police's Critical Response Team is brought in to investigate Lloyd Zuker's death. Theo lies about seeing Zuker with a gun to help Joe but his story doesn't hold up under scrutiny and lead investigator Frank Conti tries to get him to turn on Joe, threatening to charge Joe with murder and Theo with the attempt to pervert the course of justice. Despite the findings of Conti's report, Joe does have the Commissioner's support, but he's haunted by the shooting and is determined to find Zuker's missing gun and clear his name. Meanwhile, the detectives investigate the murder of a man whose body is pulled from a lake. Nicole comes out of surgery.

A body is washed ashore on a crowded beach. The detectives are quick to identify the dead man, an heir to a waste disposal fortune, as someone reported missing after reportedly falling off a yacht. The small number of people on board the yacht at the time of the accident means a limited number of suspects but leads the detectives into the investigation of the power struggles inside a divided family and the effects of violence. The investigation reminds Joe of his own troubled childhood and has him questioning his own parenting skills. Sophie and Theo compete for a spot in an undercover training course. Nicole, back at work part time, receives some good news.

After being arrested on peeping tom charges, Joe's informant Louis “The Fly” gives detectives a tip on the location of a body. The dead man, a local jeweller, was involved in an illegal immigrant smuggling operation but when the detective's locate his murderer, they discover that he is under the protection of the Federal Police who will go to any length to keep their man safe from the clutches of the local cops.

A businessman is beaten to death on his morning jog. The man was newly arrived from Brisbane, coming down to oversee a corporate takeover of a marine salvage company. The small business is short on employees but long on people with motives: a secretary with claims of sexually harassment, an owner worried for his job, and someone responsible for embezzling thousands of dollars from the company.

A groom is shoot by a masked gunman at a lavish wedding reception, but despite all the guests, the detective's efforts are frustrated when no one will admit to seeing anything. Further complicating matters is an accusation that a police officer stole a large sum of money intended for the newlyweds — and evidence points towards Shane. Joe's receives an emotional blow when he learns his first wife has decided to move to Queensland to be with her new boyfriend, taking their daughter Ruby with her. To add to his woes, the seriousness of Nicole's relationship with Shane hits home when she tells him Shane has proposed. A friendly poker game yields a key clue in solving one of the crimes.

The investigation of a road rage incident leads to the discovery of an ecstasy importing racket. For Sophie, the focus quickly turns to her personal life when Eliot's father reenters her life, wanting the opportunity to be involved in his son's life. Seeking balance in her chaotic life, Sophie is tempted to let Dirk in but a shocking discovery puts much into doubt. Nicole is having second thoughts about her impending engagement to Shane.