Having just returned from a mission to Mars, Commander Ross isn't exactly himself. He's slowly becoming a terrifying alien entity with one goal -- to procreate with human women! When countless women suffer gruesome deaths after bearing half-alien offspring, scientist Laura Baker and hired assassin Press Lennox use Eve, a more tempered alien clone, to find Ross and his brood. Before long Eve escapes to mate with Ross.

In old New South Wales a new bunch of convicts arrives including the little convict, young Toby Nelson. Consigned to a Government farm they are subjected to the cruelty of Sergeant Billy Langdon and Corporal Weazel Wesley. Toby escapes and flees into the Australian bush where he is saved from death by the aboriginal boy, Wahroonga. Together, with another escapee, the highwayman, Jack Doolan, and Wahroonga’s animal friends, they launch a spectacular mission to rescue the blacksmith, Big George, and Toby’s sister, Polly.