Henry "Breaker" Morant is an Englishman living in Australia at the end of the 19th century. When war breaks out in 1899 between Britain and the Boers (descendants of Dutch colonists), Morant and a number of Australians volunteer for duty and are absorbed into the non-regular units of the British army. Acting under orders from his commanders, Morant oversees the execution of several Boer prisoners; it turns out that one of them was German, and in order to keep the peace with Germany, Britain agrees to courtmartial Morant and two other soldiers, sentencing two to death and one to life imprisonment.