After the assassination of the Victorian police minister, Kerry appoints a new task force, Cicero, in order to find those responsible. How will Lawson and the team react to new boss, Charlie Lewis?

The assassination of the Police Minister and a war brewing on the docks throws TR into the centre of a major new task force investigation. Secondly, Shannon keeps a shocking secret from Lawson and the team during an assignment to protect a woman...

Shannon struggles to overcome the impact of a personal crisis, and must face her demons in order to save a woman’s life.

Lawson challenges Charlie’s authority to pursue his own agenda with the Marauder bikies while the rest of the team protect a journalist under threat.

Headstrong Kerry is dismissive of her own safety but when the threats are redirected to her son, her anger at the perpetrators can't be contained.

Michael has been a busy man since being fired from Tactical Response. Thanks to the squad's head honcho Kerry he's now undercover, and his job is to bring down the Raineys, a family team of cocaine importers. He sets up a buy-bust meeting in order to bring the Raineys down and coaxes Josh into becoming his wingman. The trade-off location changes at the last minute and whilst TR catches some of those responsible. Col Rainey has taken Michael and gone underground. Has his desire to prove himself to everyone put his life in serious danger? Meanwhile, Shannon finds herself face-to-face with her attacker.

Tactical Response goes into overdrive as they desperately try and to locate Michael after his undercover buy-bust goes horribly wrong. Josh starts to crumble under the guilt of letting Michael get away while Stella is furious, realising her best friend, and once lover, may not come back alive. It's a race against time as Kerry fights political red tape and the remaining members of Tactical Response do anything they can to get one of their team back safely.

Tragedy can have a profound effect on those involved. Everyone has different coping mechanisms, and Tactical Response continues to reel from a tragedy within their own ranks. Stella can barely build up strength to face the day and Christian appreciates a comforting presence from Amber. Josh, feeling responsible and immense guilt from what has happened, goes underground, deliberately avoiding contact from anyone at TR.

The Tactical Response team continue their search for the man they believe is responsible for both the Police Minister and Michael's murders, as well as Josh's possible disappearance. They find out that he steals identities off people as a means of not being caught out, and Lawson has to make a big decision in order to catch him.

With a renegade Josh risking everything to find Michael's killer, the team finds themselves chasing one of their own and are forced to confront the question of how far they'll have to go to stop him.

Tactical Response find themselves up against a carefully planned manoeuvre when Lawson and others are taken hostage by the Cuckoo as part of an escape attempt from a military courtroom. As part of the team negotiates for Lawson’s freedom, Josh and Stella follow their own investigation: searching for a bomb.

As the bomb squad work to defuse a bomb, the team are tasked to fly to Fiji to extradite a South Korean National back to Australia. Shannon also responds to Lawson's marriage proposal, sort of.