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 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 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.

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.

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.

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 body of a young Asian girl is found in a garbage compactor, leading the Kingsway detectives to an international illegal prostitution racket.