The team finds a special way to honor their mate. Stella gives Lawson a hard time about not wanting to say anything at the funeral. Kerry is shocked when her son James is arrested for assault on a flight from Vietnam. When the car they are travelling in is run off the road, James sees the men in the other car and runs. Kerry and TR then find themselves in a race against time to save him from two violent drug runners.
Tactical Respose race into town, on the hunt for Oliver Ginsberg. They learn that Ginsberg has placed a very large bomb under the city and that he has plenty more deadly tricks in store for them. Lawson finds himself in an awkward position when he must work with Dom, now a member of the bomb squad, to defuse the bomb.
TR go bush for a routine training exercise. Unbeknownst to Lawson and Josh, the younger members of the squad soon find themselves at the mercy of Oliver Ginsberg, who has rigged the forest with deadly traps. When they discover Ginsberg is on his way to the city with a van full of explosives, they realize the worst is yet to come...
A group of Afghani asylum seekers have seized control of Frankston’s Peninsula Centre and taken several hostages, including the son of the Minister for Immigration. With the siege now in its thirty-third hour, TR’s stamina is put to the ultimate test as Lawson starts to question the integrity of his key interpreter.
As TR, along with the drug squad, work to catch a well known drug gang, Kerry's efforts to save Blake, a meth cook and reformed drug addict becomes personal when, devastatingly, she finds out that her son James is battling his own addiction. Meanwhile, Josh finds himself fighting for his life when an unknown man breaks into his apartment and tries to kill him.
A runaway train ploughs through country stations on a collision course with another train. Lawson sets foot on the relentless express, unaware that he is on his own collision course with Andrew Kronin. As the final showdown beckons, Lawson will have to overcome more than just the train if he is to win back his teammates' faith.
Stella, Shannon and Josh help to settle a violent ethnic dispute. Lawson, Michael and Christian are on the trail of a volatile young couple who are desperate to get married, and meanwhile, Josh receives a drunken phone call from teenager Minka, who is the daughter of Tash, and Kerry receives a surprise visitor.
Christian is thrilled to be guarding his childhood idol, Tuvaluan Prime Minister Pell Fisher, during a visit to Australia. But the glamour of the job soon gives way to dangerous reality when it becomes clear that Pell is a target for assassination. Meanwhile, Dom's hopes of returning to Tactical Response are crushed by Lawson.
TR score a lead when an ordinary civilian unwittingly implicates himself with Andrew Kronin's gang. As Lawson pushes the man to get to Kronin, Dom takes umbrage. Dom snaps, turning his gun on TR and flees. As TR 2 track down Dom, Lawson exults when he recovers a substantial amount of the heist money.
As Lawson's growing obsession with the robbery crew threatens to pull Tactical Response apart, Josh shows his leadership as TR2 assist Drug Squad with the arrest of a drug importer. But things aren't as simple as they first seem when TR discover the offender's niece has been kidnapped and held to ransom. Josh must race to save the girl, in the process meeting her mother, Tash, who will change everything.