Western Australia, May 1915. 18-year-old Archy Hamilton (Mark Lee) is an idealistic young Australian rancher with a talent for running sprints. He is trained in sprinting by his uncle Jack (Bill Kerr) and idolises Harry Lascelles, the world champion who ran a 100 yard sprint in less then 10 seconds. World War I has has been raging for a few months, and Australia is putting together regiments to help the British war effort. Since he can ride, young Archy wants to enlist in the Light Horse and be sent abroad to fight in the war as a duty of honor for his country.
One day during a cattle roundup, Archy gets into an argument with a local rival and bully, Les McCann (Harold Hopkins), and they soon race against each other, under the condition that Archy will run bare-foot, and Les will ride his horse bareback. Les falls off his horse and Archy wins, but his feet are horribly mangled by the trek, with only a few days to recover for an athletics carnival.
During this time of recoperating at home, Jack reads 'The Jungle Book' to the younger children of the family as a bedtime story, when Archy walks up and listens at the door. A passage where Mowgli reaches manhood, loses his innocence, and must leave the family of wolves that raised him is given particular prominence. Archy's political beliefs are influenced as well, as he hears several conversations taking place that convince him of the need to join the military. Eventually, Archy and Jack journey to the athletics carnival in the nearby town.
Meanwhile, Frank Dunne (Mel Gibson) is an erstwhile railway labourer who is definitely down on his luck. He's a fast runner though, and tries to get some prize money at the athletics carnival race, but is defeated by young Archy, comming in second. After the race, Archy tells Jack that is is not coming home, but wants to enlist to flight in the war. He gives Jack all the prize money that he won, but keeps his winning medal as well as Jack's stopwatch. Jack reluntantly lets Archy go to enlist, but tells him that he does not expect him to return home... ever. Archy goes to a recruiting station to enlist, but is rejected by the local recruiter (who knows him) as he is underage (men have to be 21 or older to enlist).
At a local tearoom, Archy meets with Frank and explains to him that he wants to join the Army and get involved in the war. Unfortunately, since Archy is underage, Frank suggests they travel to Perth on the west coast, where he is unknown, in order to enlist. Both he and Frank are flat broke, so they hop on a freight train for a free ride, but are left in their sleep at an isolated desert station the next morning. They wind up walking across the desert using Archy's wilderness survival skills, all the while arguing their political beliefs. After meeting a camel rider who points them in the direction of Perth, Archy and Frank stop for the night at a nearby plantation, and from there to Perth itself where they shack up with Frank's father who still resides there.
Frank, who is of Irish descent, has little desire to fight for the British; however, bonds of mateship make him try for the Light Horse with Archy. He cannot ride, so he joins the infantry instead with three old mates in similar straits: Billy (Robert Grubb), Barney (Tim McKenzie) and Snowy (David Argue), who used to work with him along the railway line. Many of the motivations that compelled young men to join up appear: the propaganda associated with German atrocities in Belgium, the sense of adventure, the attraction of a smart uniform and the pressure from society to "do your bit." After enlisting, they are quickly embarked on a transport ship bound for the Mideast. At this point, Frank and Archy are separated as Archy goes off on one transport ship with the Light Horse, and Frank and his three friends board another ship.
Moving forward to a few months later in July 1915, Frank and his three mates are in Egypt for training, encamped near the Pyramids, and spending their free time in Cairo, drinking, haggling with local merchants and visiting brothels. They express their contempt for the Brits during a rugby game near the Pyramids.
One day, during a shambolic training exercise in the desert, Frank and Archy meet once again, and Frank is able to transfer to the Light Horse, as they are now being sent to the Gallipoli Peninsula as infantry, sans horses. After a formal going away party for the troops of Australia and New Zealand, Frank and Archy pack up and leave for their destination and destiny - Gallipoli, a narrow mountainous peninsula on the Turkish Ottoman European coast.
Frank and Archy arrive at Anzac Cove in the dead of night and over the next several days, endure the hardships and boredom of the trench warfare that prevailed for much of the campaign.The ANZAC (Australian/New Zealand) forces are crowded against the shore, heavily dug in for protection against frequent enemy shellfire. In one place, the only route through to the front line involves running across a gully with a Turkish machine gun at the far end!
During one night where reinforcements of Australian infanty arrive, Frank is reunited with his three friends and the four join with Archy for some casual talk. Frank's infantry mates fight in the Battle of Lone Pine on the evening of August 6, 1915. (The fighting is implied but not depicted.) Afterwards, Frank finds Billy shellshocked on the beach after the battle and tells Frank what happened to the others: Barney was shot and killed, and Snowy is in a hospital severly wounded during the taking of the Turkish trenches at the Lone Pine plateau. Frank visits Snowy at the infirmery where he sees that he is in such bad condition that he is not being given any food or water or medicine. Aware that he may be mortally wounded, Snowy asks Frank to take his diary and have it sent to his parents back home.
The following morning, Archy and Frank take part in the charge at the Battle of the Nek which is to act as a diversion in support of the British landing at Suvla Bay just up the coast. Archy is told by his commander, Major Barton (Bill Hunter), that he will be the runner, but he refuses the offer in order to save Frank from going into battle and having the risk of being killed. Frank is then made the runner and courier for the regiment commander.
The 8th and 10th Light Horse are to attack in three waves across a narrow stretch of very open and exposed ground only 20 to 25 yards wide which is guarded by several by Turkish machine guns. The first wave is timed to go at dawn at 4:30 AM, at the end of an artillery bombardment. At dawn, the artillery guns of the Australian army and of Britsh Royal Navy off shore unleashes a terrific bombardment on the Turks. Unfortunately, the Major Barton's watch is off by a seven minutes. He waits for the battleships to "finish them off" before sending his men over the top. This gives the Turks time to re-man their machine guns. Seeing the Turks re-occupy the trenches, Barton phones his superior, Colonel Robinson, who insists the attack proceed.
The first wave of around 150 Austrian Light Horse troops goes over the top and is mercilessly cut down by a storm of rifle and machine gun fire within 30 seconds. A minute later, right before the second wave goes over, Archy recognizes his old rival Les and realizes he is about to go over with the second wave. The second wave of 150 Australians goes over, and Les is one of the first shot and killed. During the confusion, telephone lines to HQ are disrupted, so critical information cannot be relayed.
Frank is sent running at top speed to tell HQ that the attack has failed, and that further assaults will be futile as well. But the arrogant and slightly insane Col. Robinson (acting on false information) believes that it has partially succeeded and he orders Frank to tell Barton that the attack continue at all costs.
Frank returns to Barton and suggests he go over Robinson's head to the division commander, General Gardner. The dull-witted and frightened Lieutenant Gray (Peter Ford), Barton's aide and second-in-command, admits to Barton that he was the soldier who said to Robinson that he saw marker flags just before the telephone lines went dead. However, Gray only heard there were marker flags in the trenches but does not know who said it and that it must have been one of the soldiers before he went "over the top" and was killed. Barton sees that no attacking Australian got more then 10 yards from their trench. On Barton's orders, Frank hurries to Gardner's headquarters down on the beach to get permission to cancel the attack. Frank is forced to run across the gully with the enemy machne gun at the far end, but makes it.
On the beach, The General, hearing from a radio operator that at Suvla Bay, "the British soldiers are sitting on the beach drinking cups of tea", gives Frank the message that he is "reconsidering the whole situation", effectively cancelling the attack on the Nek ridge. As Frank sprints back, the phone lines are fixed and the cynical and crazed Robinson orders that Barton continue to attack at all costs... even if it means the entire destruction of the Australian Light Horse. Barton considers joining his men in the final and futile charge and decides to do so aware that they are all going to die in the charge.
After being given time to pray, write letters, and save their possessions to be sent to their families knowing they are about to attack an impregnatable enemy position and they are all going to die in the progress, (Archy's possessions are the running medals he earned with Jack), Barton personally leads Archy and the rest of the 150 Australians of the third wave as they go over the top and they are all cut down by Turkish fire. Frank arrives only seconds after the men are sent over, and lets out a scream of despair.
The final shots show Archy, the sprinter, running across no-mans-land as hard as he can towards the Turkish trench... his rifle gone. He almost reaches the trench, when he is hit several times in the chest by machine gun fire. He begins to fall...
The final freeze-frame on Archy being fataly gunned down is an image that evokes Robert Capa's famous 1936 Spanish Civil War photograph of a soldier at the moment of death called 'The Falling Soldier'. The image slowly fades to black.