French-Canadian fur trapper Jean La Bête, Oliver Reed, paddles his canoe through wild waters toward a frontier settlement to sell furs. At the seaport, a steamboat lands as the Trader, Rex Sevenoaks, and his mute foster-child Eve arrive to fetch mail and consumer goods. The Trader explains to Eve that the ship brings “Jailbirds … from the east,” and that “their husbands-to-be had bailed them out and paid their fines and their passages with a guarantee of marriage.” Later, the captain is auctioning a woman because her husband-to-be has died in the meantime. Jean La Bête decides to take his chance to buy her but makes his bid too late.
Native Americans Yellow Dog and No Name have told the Trader that La Bête is dead. The Trader, heavily in debt, has spent money he owes La Bête so that when La Bête calls to collect his dues, the trader has to use his own savings. Next day, the trader's wife Barbara Chilcott, to compensate for the loss of her savings, offers Eve for a thousand dollars to the simple-minded, rough-cut trapper. She explains that Eve's inability to speak is caused from the shock she suffered when she had to witness how her parents were murdered years before.
La Bête agrees to buy Eve and takes her against her will into the wilderness of British Columbia. Eve rejects La Bête's advances. La Bête takes her hunting and acquaints her with the wilderness but here, as well, he fails to win her trust. Eve defends herself from his advances with a knife.
One day, on checking his traps for caught animals, La Bête is threatened by a cougar. He shoots the cat but gets his foot into his own bear trap. Badly injured, he tries to drag himself back to his hut, hunted by wolves. Eve is waiting at the cabin and hears the howling of the wolves approaching the hut. She takes a gun and sets out in search for La Bête; together they get rid of the wolf pack. La Bête's lower left leg is broken, so he asks Eve to bring the medicine man from the next Indian village, a two days trip away. The winter has come, so Eve starts an arduous walk over snow-covered hilltops. She eventually reaches the village only to find it deserted.
Returning empty-handed, Eve finds La Bête already suffering from blood poisoning. He urges Eve to cut off his poisoned leg with an axe. After La Bête has tried to stun himself by gulping rum, Eve complies, and he passes out from pain. Eve nurses the trapper, is forced to learn to hunt on her own and becomes capable of providing for the couple. Eventually, after La Bête learns to say 'please' to her, thanks her for saving his life and declares that he could not live without her, they have sex.
The morning after, Eve seems to regret her decision and leaves the cabin, holding a rifle against La Bête who follows her to the river, angry and perplexed. Eve flees in his canoe. Her journey is fraught and she is thrown from the canoe in white-water rapids. The empty canoe is found by native Americans and Eve is rescued, and taken back to the settlement where she was taken from. Although welcome, she remains an outsider. She remains in bed for two months and loses the child she was carrying. Her family arranges a marriage for Eve to a man who previously flirted with her. Eve does not appear happy, however.
On the day of marriage, her foster-sister and foster mother dress her whilst the foster-sister demands to know how she lived in the wild, and if she killed La Bête. Eve runs away again to return to Jean La Bête. She arrives on the river beach, and La Bête welcomes her home by telling her to clean the house. Eve smiles. She later watches La Bête hobbling into the forest while singing. Eve chops wood and carries it into the cabin.
