Set in New France during 1634 and the Beaver Wars, the film traces the formative days of a settlement that will one day become Quebec City. Jesuit missionaries push to convert the Algonquin people, while Samuel de Champlain, the founder of the settlement, Jean Brousseau sends Father LaForgue Lothaire Bluteau to join a Catholic mission in a distant Huron village. With winter approaching, the journey promises to be grueling, spanning as much as 2,400 kilometres across lakes and forests.
LaForgue is joined by a non-Jesuit assistant, Daniel Aden Young, and a guiding party of Algonquin led by Chomina August Schellenberg, his wife Tantoo Cardinal, and Annuka Sandrine Holt. The group traverses ice and woods, forging a fragile bond as Daniel and Annuka fall in love, challenging the priest's celibate vow.
Along the way, they encounter a band of Montagnais hunters; Mestigoit Yvan Labelle, the Montagnais shaman, grows suspicious and jealous of LaForgue's influence, urging Chomina and the others to abandon the two Frenchmen and seek a winter lodge. The Algonquin decide to move, and Daniel chooses to follow, insisting on staying by Annuka's side.
When a Montagnais hunter tries to shoot Daniel, Chomina is wracked with guilt for betraying Champlain's trust. He and a handful of Algonquin return with Daniel to search for LaForgue. A Mohawk Iroquois raid ensues, killing many Algonquins and taking the rest captive. The prisoners are forced to run the gauntlet and to witness Chomina's young son killed. Annuka seduces their guard, uses a caribou hoof to knock him unconscious, and makes a break for freedom. On his deathbed, Chomina envisions the grove he has dreamed of many times and, in that moment, the She-Manitou Linlyn Lue appears to him.
With the winter deepening, Annuka and Daniel guide LaForgue toward the outskirts of the Huron settlement, but they leave him outside, as Chomina had foreseen. LaForgue reaches the surviving Hurons, most of whom are dead or dying after a smallpox epidemic and blame the French mission for their suffering. The last survivor's leader asks for baptism, and when asked whether he loves them, LaForgue replies that he does, and performs the rite. The story closes on a golden sunrise, and an intertitle reveals that fifteen years later the Hurons have accepted Christianity but are crushed by their Iroquois enemies; the Jesuit mission to the Hurons is abandoned, and the Jesuits return to Quebec.
