In childhood, William Wallace (JAMES ROBINSON) doesn't know much about the fighting elsewhere that pulls in his father, Malcolm (SEAN LAWLOR), and his brother, John (SANDY NELSON). All he knows is that the English are causing trouble, and that's fodder enough for making animal skulls representing those enemies and throwing rocks at them with his friend Hamish (ANDREW WEIR).
But William's world changes when his father and brother die in battle, and he's taken in by his uncle Argyle (BRIAN COX), who teaches him the ways of the world crucial to him in order to think first with his wits before taking up a sword. Now a man, William (MEL GIBSON) returns to his home, his friend Hamish (BRENDAN GLEESON), and Murron (CATHERINE MCCORMACK) who he's loved for a very long time.
Despite the English king, Edward the Longshanks (PATRICK MCGOOHAN), deciding that he should be the one to rule Scotland and not those clans who squabble for power, and causing trouble by way of making newly-married men give up their wives for one night to the "noble lords" of the various areas of Scotland as a way of "blessing" the marriage, William stays out of the way. He marries Murron in secret. But then his world twists him hard again when Murron is killed by the local lord, and he realizes the injustices Edward is placing upon Scotland.
He has his wits, and he takes up a sword and gathers up men to fight the English before they make things worse. Even while he inspires men and becomes a legend through their words all over Scotland, there are those who doubt the necessity of breaking from England completely. They want the lands and the comforts, such as titles, afforded them by being connected. They have those things, so why should they want to do anything that would risk that?
To William, however, freedom is the most important thing. Without freedom, there is no hope, there is nothing to strive for. He and thousands of other men engage in long, bloody battles, with Edward trying to stop the rebellion, even employing his son, the prince of Wales (PETER HANLY), to try to get rid of the problem, though without much luck because he's not as ruthless as his father and Edward is contemptuous of that fact. And the battles rage on.