Stone and Angie go undercover to investigate the murder of a young Asian woman involved in the X-rated movie business. MacKenzie receives a compromising photograph relating to her former relationship with Church.

The compromising photograph of MacKenzie and Church threatens the security of the entire unit. Church pursues the source of the photos while Angie and Stone push for more information on the Porn Star murderer.

Church works undercover as a safecracker to find out the target of the robbery, discovering that the gang have a one-off, get rich quick scheme.

Rocca finds himself in unfamiliar territory when he goes undercover with Church on a case involving gold smuggling and political intrigue.

The Unit pull off a successful cocaine bust, leaving drug lord, Bryce Forbes, wanting revenge. Acting on information supplied by Forbes' lover, Heather, Stone is sent undercover to infiltrate the drug lord's operation.

MacKenzie goes undercover in a woman's prison. Her target is Nancy, a young woman convicted of murdering her husband, who embezzled millions of dollars in an investment scam. The Unit's aim is to recover the money.

Stone and MacKenzie infiltrate a gang planning to rob and murder a coin dealer. When they lose contact with the Unit, Rocca must second guess their movements.

Church is due to give evidence in court against major crime figure, Dino Rossi, but the Unit discovers someone wants Church silenced before he can testify.

MacKenzie works closely with Maddern, a psychological profiler, to identify a killer who uses the internet to select his victims. With the Unit in full-scale back up, Mac is put undercover as bait.

Working undercover as an ex-army officer, that now supplies illegal explosives, Stone encounters his first girlfriend, Kelly, entangled in a contrabrand arms export scam.

While investigating large scale thefts on the docks, Church accidentally shoots an old mate, Tony. While Church is suspended, the Unit continues to uncover the extent of the shipping robberies.

Stone leads a sting on a well known crime family that doesn't quite go to plan as the eldest son, Billy, escapes. Stone and Angie lay low at Stone's family farm, but Billy tracks them down.

When the daughter of a Family Court judge is abducted, Church teams up with Rory, a young Undercover recruit, and together they investigate a group lobbying against the judge.

While investigating a heroin racket, Church encounters his nephew, Matt, who has fallen victim to the needle. Church spends time with Matt, experiencing the emotional, rather than criminal, side of heroin addiction.

Undercover with Angie and Stone, Church investigates a series of strategic truck-hijackings which have turned to murder.

When the husband of a leading Aboriginal activist is car-bombed, Stone and Angie go undercover to investigate SWARM, a radical right-wing group suspected of involvement.

When A.J, one of MacKenzie's informants, finds out that the adoption of his young Vietnamese daughter wasn't strictly legal, Church and MacKenzie uncover a ring of child smugglers.

By using Stone's informant, Rocca plans a dangerous drug operation to land a well known drug heavy. The drug operation is put at risk when Stone's informant goes into labour and Church is left holding the baby.

Church and Mac go undercover to infiltrate a group of high-roller gamblers who conduct illegal gaming sessions. The sting takes a bizarre turn when the gaming session is raided, not by the police, but by robbers.

When Rocca is shot outside his home, Church becomes obsessed with finding the gunman. Mac assumes she will fill in for Rocca so there is friction aplenty as a new boss joins the ranks.

Church meets a new informant, Terry Hanks, who repeatedly delivers big time drug dealers, but when Terry offers to land them 'The Dingo', the biggest and baddest dealer of all, Mac and Church have their doubts.