When his best mate and partner is killed in a random attack, Detective Gary Hyde and his new partner Claire McKenzie discover an underbelly of murder and fraud that threatens national security.

Gary and Claire travel to Hong Kong in the hunt for Nick's killer, and uncover a terrorist network operating inside Australia.

Gary and Claire track a suspected terrorist to Far North Queensland and intercept a smuggler with a deadly cargo. Meanwhile, Tanya and Kevin uncover a money laundering operation with a difference.

Claire is held hostage in a deadly bus hijack, as Gary comes face to face with the terrorist who murdered his partner.

Gary's marriage is tested when he travels to Indonesia with Claire to investigate a terrorist suspect. Tanya and Kevin suspect there is a mole within the Task Force.

A deadly Mosque bombing proves Claire's suspicions of a traitor inside the Task Force. Gary and Sonya's marriage faces a crisis when their son Oscar has a health scare.

Gary and Claire take the law into their own hands to find the terrorists threatening national security. A power struggle within ASIO threatens to derail the Task Force's investigation. Sonya realises she holds the key to Gary's investigation.