A suburban printer is killed in a car bomb attack. National Security sends Senior Agent Richard Skerritt to work the case. As the Major Crime team and Agent Skerritt begin to work together, each wonders if they can trust the other. When a young boy goes missing on his way home from a Muslim school, Malik knows that he must discover the truth and the boy's whereabouts, as soon as possible.
Zane Malik is working with National Security's Richard Skerritt to track down the car bomb killers. The prime suspect is a Lebanese businessman, Akmal. He's suspected of being an arms dealer, but the only way to get the truth is to get inside. Malik agrees to go undercover, leaving a gap in the Major Crime investigative unit.
Detective Zane Malik is deep undercover and in danger. Can he link an arms dealer, Akmal, with the car bomb murder of an NSO agent? Agent Skerritt is positive there's a connection. When Akmal's girlfriend is killed, he orders a hit on the man who killed her... and he wants Malik to do it.
An ambulance officer is stabbed to death by a kid in an drug-induced rage. Detective Sonny Koa delivers the news and bonds with the victim's family. The mother of the deceased extracts a promise from Koa: she wants her son back, in one piece, for burial. Meanwhile, the mystery surrounding the dead NSO agent deepens.
A trip to Canberra with the widow of the murdered NSO agent leads Malik face-to-face with an old foe. But his absence from Major Crime causes problems as the squad investigates a mysterious crossbow killing. Inspector Wright juggles professional and personal problems, as her own brother is the target of a hitman.
Inspector Wright and the Major Crime team unite to track down the men behind the attempt on her brother's life, at the same time trying to prevent Wright's father from seeking vigilante justice. Meanwhile, a respected transplant surgeon is murdered. Malik's wife, fed up with his obsession with work, makes a startling decision.
When a truck driver is killed and a haul of fertilizer stolen, Malik and Skerritt fear a possible terrorist attack. The race is on to find the men responsible. Is this event connected with the car bomb that killed Agent Angleton? Malik knows he must do everything in his power to stop another catastrophe, including using his connections in the Muslim community and putting his life on the line.