Following his demotion, Gus and Jasmina investigate who really shot down Flight BM-24 while Ethan and Kath narrow their malware suspects to somebody within A-Crew.

As tensions in the South China Sea remain at breaking point, Gus and Jasmina's relationship stumbles and the US prepares to launch an airstrike on a Chinese-claimed island.

A team of talented Australian and American intelligence analysts work together to ensure global stability in one of the world's most important and secretive joint intelligence facilities - Pine Gap.

Kath, Ethan and Rudi discover each of the malware suspects has ample motives, and the unpredictable US President orders a US warship to undertake a provocative voyage through the South China Sea.

Jasmina discovers a secret Australia will do anything to hide, while embarrassing audio is leaked of the American President that further damages the US and Australian relationship.

In a race against China, A-Crew desperately scour the South China Sea for signs of the missing US pilot while the net closes in on the Pine Gap mole.