British diplomat Ian Porter is apprehended at Heathrow airport in possession of 20 kilos of heroin. Porter's unwillingness to co-operate leaves Scotland Yard Inspector Julie Hales believing he is doing business with Russian arms and drugs trafficker Sergei Krousov.

Unaware that Krousov has intentions to sell a suitcase bomb, Scotland Yard offers to cut Porter a deal to turn on Krousov. In return, they'll grant him immunity from prosecution and entry into their International Witness Protection Scheme.

Chief Inspector Hales accompanies Porter and his wife Pippa to Sydney, where chameleon Porter believes his handler at MI6 can manipulate the Australian Federal Police protection team to allow him to complete his mission.

Australian Federal Police agent Mark Wilson and Hales have no idea of Porter's MI6 links, so when their security is stunningly breached all hell breaks loose.