The sophisticated holdup of an armored vehicle leaves four dead. One of them is an armed robber, with an enigmatic identity, leaving Major Crime to ponder the possibilities. Is this an ordinary bunch of thieves looking to get rich quick, or is there a more sinister motivation behind the robbery?
A Somali teenager is found viciously bashed to death in a lonely railway tunnel. The investigation leads Koa and Malik to a Somali man who is rumored to be recruiting Somalis to return to Africa to fight for Al-Shabaab. Meanwhile, Internal Affairs investigates the shooting of Mahmoud, an accessory in the armed robbery, which causes conflict between Malik and Travis.
The double murder of a Jewish couple leaves few leads. According to the woman's son, a large amount of cash is missing, along with the Palestinian student who was living with them. But the woman's son is lying about critical evidence, and the conflict between the two detectives, Travis and Malik, spreads from the Middle East to the unsolved crimes of multiple murder and armed robbery.
Inspector Wright becomes personally involved in a case when a young woman is found raped and murdered after getting into a taxi. The suspect is the same man who had previously walked on a similar charge, and now Wright sees an opportunity to put the man away for a long time. Meanwhile, Malik works to find the gang responsible for the armed robbery.
Detective Sonny Koa is enlisted to help the son of a friend, Sam, who's involved with Maori gangsters. When the kid is implicated in a violent robbery, Sonny must walk a fine line between his obligations as a cop and his obligations to his community. Meanwhile, Malik is focused on nailing the armed robbery gang. He has a suspect in custody who knows the truth, but he refuses to talk.
Malik hopes that a visiting Afghan cop can provide some answers to the mystery of the armored car robbery and its connection to a massacre of civilians in Kandahar. But the visitor is killed before Malik can talk to him, and Detective Travis is behaving erratically. Detective Lim undertakes her own investigation to discover what he's trying to hide from her and the rest of the Major Crime team.
Two youths are shot dead while fishing. When another body is discovered in nearby waters, it seems the boys were killed because they witnessed an execution. The case is connected to the armored car robbery, and Malik discovers Travis knew one of the dead gang members when they served together in Iraq. What he can't figure out is what secret Travis so desperate to keep buried.