In 1961, the Australian spy agency ASIO secretly recorded meetings between a senior KGB officer, Ivan Skripov, and a woman codenamed 'Sylvia'. The case culminates when Skripov sends Sylvia to Adelaide with the intention of delivering messages to a KGB agent. ASIO believes that this is espionage of British nuclear tests in the desert of South Australia. However, when the KGB operative did not show up, there was a case of collapse. Six decades later, director Peter Butt re-examines ASIO's surveillance footage and discovers that the mysterious KGB agent was indeed in Adelaide. He identifies a KGB agent and discovers that he was killed shortly after Sylvia's final meeting.