Stone and Angie go undercover to investigate a murder believed to be linked to a pornographic film industry. Meanwhile MacKenzie receives compromising photographs related to her past relationship with Church.

MacKenzie pushes Angie and Stone to solve the ongoing porn murder case, as the compromising photographs of herself and Church threaten the security of the Unit.

The undercover unit faces a dilemma when the life of Church's informant is threatened. Should they abort the sting?

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

Rocca goes undercover with Church on a case involving goldsmuggling, political intrigue and attempted assassination.

Mackenzie goes behind bars to investigate a murderer suspected of grand scale embezzlement.

The Unit work to protect a coin dealer they believe will be the target of a revenge attack.

The Unit discover there is a contract out on Church's life. Someone wants him silenced before he can testify.

Working closely with a psychological profiler, Mackenzie puts her life on the line to trap a serial killer who uses the internet to select his victims.

Working undercover in an explosives trading investigation, Stone allows his heart to rule his judgement, putting the operation and his life at risk.

During an undercover operation, Church is involved in a shooting accident which brings him under scrutiny from Internal Affairs.

Working undercover in the music industry, Angie's life spins out of control as she begins to question her future in Undercover.

When Stone becomes the target of a revenge attack, Angie and his family get caught in the crossfire.

Church must team up with a new recruit to investigate the abduction of the daughter of a Family Court judge.

Church uses unorthodox methods during a drug investigation when he discovers his nephew, Matt, caught up in the cycle of addiction.

The Unit investigate a series of truck hi-jackings that have led to murder.

Following a car bomb attack, Stone and Angie go undercover to investigate a radical right-wing group suspected of race terrorism.

When Church and Mackenzie team up to investigate an illegal adoption racket, Mackenzie's informant decides to take justice into his own hands.

A routine drug bust takes a sudden turn forcing Rocca to take the place of the target, while Church faces the challenge of a lifetime as he deals with a pregnant informant.

The unit become involved in a robbery and double murder when they go undercover to infiltrate a group of high-rolling gamblers using black money.

Church breaks all the rules when he goes after Rocca's attacker and ends up head to head with the new boss of Undercover.

The Final episode of the year for the Melbourne-based cop drama finds undercover operative Church caltivating a new informant. And this man's information is amazingly good. While the future of the undercover operation is under threat, Chruch has serveral meetings with his informant, Dingo. Finally, he extracts details with will enable the Singers group to bust a big-time drug ring. But there's a twist in the tale which makes this one of the most satisfying episodes of the series this year.