[1][2][3] The title character, John Hunter, was an agent working for SCU3, a sub-division of the ASIO-like COSMIC (Commonwealth Office of Security & Military Intelligence Co-ordination).
However, he was quickly overshadowed by the show's main antagonist, Kragg, an agent employed by the Australian operation of the CUCW (Council for the Unification of the Communist World).
[4] SCU3 was the Melbourne-based arm of COSMIC, headed by Charles Blake (Nigel Lovell), with offices in the former National Mutual Centre building or St Kilda Road.
Most episodes were directed by Ted Gregory, a longtime Crawford studio director, with Jones supervising a lean and mobile film unit.
Notably, a first season arc, "The Prometheus File," was set at the high-security Woomera Rocket Range and featured actual footage of the Blue Streak launch, with the actors even allowed access to the tallest gantry for the climactic fight.
[4] Kevin Sanders, a GTV-9 news journalist and announcer, supplied the opening narration setting up the lead character and premise over the main title sequence.
[4] In a concession to the character's popularity, Kragg ultimately defected to the side of good after being wounded when his girlfriend (played by Patricia Smith, later cast in Division 4) was savagely killed.
Series star Tony Ward had been somewhat dissatisfied with the direction his character was taking with the increased emphasis on Kragg, and commented that the high output of episodes by this stage had outstripped the ability of the writers.