Alexander III of Scotland passes away in 1280 leaving no heir. Scotland is invaded and conquered by King Edward Longshanks, and his actions are witnessed by a young William Wallace. After the death of his father he is taken in by his Uncle Argyle, who takes him overseas on a pilgrimage through Europe, where Wallace also begins to study.
In 1297 Wallace returns to Scotland and is reunited with his childhood friend Murron MacClannough, with whom he falls in love. They marry secretly. MacClannough is the victim of an attempted rape by English soldiers. Wallace fights them off to save her but they try again, and this time in an attempt to defend herself, Murron is captured and executed in public, as a warning to others not to fight back. Wallace gathers his clan together to slaughter the English garrison in town.
Longshanks' son, Edward, is ordered to stop Wallace by any means necessary. However, he has not bargained on the growing popularity of his foe. News of Wallace's actions is spreading like wildfire, and Scots from surrounding clans rise up and join him. He leads his self-made army to victory at the Battle of Stirling and manages to kill Longshanks' nephew at the Battle of York. He executes him and sends his head to the king.
Robert the Bruce, son of Robert the Elder, is a contender for the Scottish crown. Wallace seeks his help, knowing that Robert's father thinks the best way to secure the throne for his son is to do whatever the English tell hm to do. However, despite seeming weak by doing this, he is actually very dominant over his son. Wallace believes that by banding together and rebelling they can rid Scotland of the English and secure the throne for the younger Robert at the same time.
Meanwhile, Longshanks plans an invasion but needs a diversion. He sends his daughter-in-law, Isabella of France, to negotiate with Wallace, hoping to keep him occupied whilst the invasion takes place. The plan backfires, because Isabella rather likes Wallace when she meets him in person. She tells him about the planned invasion and Wallace springs into action. He asks the Scottish nobility to join him in action to counter the threat of the English invasion. He also asks Robert the Bruce to lead the force.
In 1298, Longshanks leads his own army to Falkirk where he confronts the Scots. Nobleman Mornay and Nobleman Lochlan are easily bribed by the King and turn their backs on Wallace. The betrayal is compounded by the discovery that Robert the Bruce was allied with Longshanks from the beginning. After the battle is over, Robert sees what harm he has brought to his country and he swears that he will never again choose the wrong side.
To punish Lochlan and Mornay for their betrayal, Wallace kills them, then leads a guerrilla offensive against the English that lasts seven years. His biggest ally is Isabella, with whom he has an affair. However, betrayal is still in the air. Robert senior invites Wallace to a meeting in Edinburgh, ostensibly to talk strategy, but he has conspired with the English yet again, and actually plans to hand him over to them. Robert the Bruce learns of his father's plans and disowns him, whilst Isabella gets revenge of her own by telling Longhanks that she is pregnant with Wallace's child; his bloodline will be destroyed upon his death.
Wallace is brought before a magistrate in London on charges of high treason. Found guilty, he is sentenced to torture, and public execution. Whilst he is hanged, drawn and quartered he maintains his resolve and his independence, and refuses to submit to the king. The crowd are impressed and moved by his strength of heart and they begin to call for mercy. The magistrate offers him one last chance. All he needs to do is say the word "mercy" and he will be given a quick death. Wallace shouts, "Freedom!" and his death is ordered. As he is decapitated he sees Murron in the crowd; she is smiling at him.
Robert, now King of Scotland, leads a Scottish army to a ceremonial line of English soldiers at Bannockburn Fields, where he is supposed to formally accept English rule. He invokes Wallace's memory by throwing his sword to the ground in front of the English army, and calls for his men to fight as valiantly with him as they did with Wallace. He leads the army against the English and finally wins the Scots their freedom.
The sun sets on a free Scotland, with Wallace's sword planted firmly point down in the middle of Bannockburn Field.
