In Medieval Scotland, Merida, a young princess of the clan Dunbroch, is given a bow and arrow by her father, King Fergus, for her birthday. Her mother, Queen Elinor, is dismayed. While venturing into the woods to fetch a stray arrow, Merida encounters a will-o’-the-wisp. Soon afterward, Mor’du, a huge demon bear, attacks the family. Merida flees on horseback with Elinor, while Fergus fends off Mor’du, though the fight costs him one of his legs.
Now a teenager, Merida discovers that to her dismay, she is to be betrothed to the son of one of her father’s allies. Reminding Merida of a legend of a prince whose pride and refusal to follow his father’s wishes destroyed his kingdom, Elinor explains that failure to consent to the betrothal could harm Dunbroch.
The allied clan chieftains and their first-born sons arrive to compete in the Highland games for Merida’s hand in marriage. Merida twists the rules, announcing that as her own clan’s firstborn she is eligible to compete for her own hand. She easily bests her suitors in an archery contest, shaming the other clans. Later, she and Elinor argue and Merida leaves. After following the wisps to the hut of an elderly witch, Merida bargains with her for a spell to change her fate.
When Merida gives the spell, in the form of a cake, to Elinor, it causes Elinor to transform into a bear, though still retaining most of her human personality. Merida returns to the witch’s cottage with Elinor, only to find it deserted, and discovers a message from the witch: unless Merida is able to “mend the bond torn by pride” before the second sunrise, the spell will become permanent. Merida and Elinor are led by the wisps to ancient ruins, where they encounter Mor’du. Realizing that Mor’du was the prince in the legend, Merida vows that she will not let the same thing happen to her mother, and concludes she needs to repair the tapestry she damaged during their argument.