In 1914 men of colour were expressly forbidden from joining the Australian Imperial Force but a number like Aboriginal man Robert Green, enlisted anyway. Deployed to Gallipoli, Green becomes a skilled sniper earning fame as “Killer Green”, a nickname he deplores. As the campaign progresses Green's skills and intelligence are recognised by Brigadier John Monash. Monash employs Green to good effect, and protects him from military justice when Green assaults an officer who was unnecessarily endangering his men.
Following the withdrawal from Gallipoli, army life provides Green with promotion and a level of acceptance he had never before experienced. However when Monash renews their working relationship Green is thrust into a world of espionage and murder. Monash, now a General, supports an MI6 mission to assassinate the head of the German Secret Service and he sends Green to France to make the hit.
To reach his target Green is plunged into the horror of the battle of Pozieres which he must survive if he is to carry out his mission.