In the 1840's, the pioneering days of the Australian bush country, Irish patriot Captain Michael Fury is arrested for his politics and shipped to an Australian penal colony to serve his sentence. Upon his arrival, Fury and his fellow prisoners are farmed out as slaves to Arnold Trist, the despotic land baron who considers himself the law, enforcing his edicts with whipping posts. After making a daring escape from prison, Fury meets Jeanette Dupre, the daughter of strict Mennonite François Dupre, and learns that Trist is trying to drive the settlers from the valley so that he can seize their land. Over Dupre's objections, Fury organizes the settlers to take action against Trist and returns to prison to recruit the convicts to the settler's cause. When Trist begins his campaign of terror at the Bailey ranch, Fury, abetted by convicts Blackie, Coughy and Bertie, rides to the rescue and thwarts Trist's men. As stories of Fury's escapades filter back to Sydney, the Governor of Australia decides to visit the back country and investigate. Meanwhile, Jeanette falls in love with Fury, and when her father forbids her to see him, she runs away. In revenge, Dupre tells Trist the location of Fury's hideout, but Trist double-crosses the Mennonite and imprisons him. The fugitives escape Trist's ambush, but when Dupre's house is burnt down and a charred body found in the ruins, Fury is arrested for the murder of Dupre and sentenced to hang. As the governor interrogates Fury before his execution, Blackie hears Dupre calling from his cell, rescues him and presents him, very alive, to the governor. His duplicity exposed, Trist attempts to escape, but is shot by a dying Coughy. After hearing the evidence, the governor grants Fury a pardon and places Blackie and Bertie in his custody.