Part of a series on Ginger Snaps
The film states that each spring a party from the fort traveled to Hudson Bay to trade pelts for winter provisions but in 1815 the party never returned. This is when the story begins. Brigitte and Ginger are lost with their horse in the Canadian wilderness when they come across a seemingly abandoned camp. They then notice an elderly Indian woman, who gives Ginger and Brigitte each a necklace with a bird's skull. The woman speaks of them as the red and black, and warns that unless they "kill the boy" one sister will kill the other. Suddenly the girls' horse is startled and flees. While running after their horse, Brigette's foot got trapped in a hunter's snare. Ginger goes back to the camp to find the Indian woman, but the hunter arrives before Ginger returns. He releases Brigitte and leads them to Fort Bailey where they take refuge. Ginger claims they are the daughters of a trader who drowned, seeking passage East.
The fort has been under siege by werewolves for some time. The sisters are taken to the doctor, Murphy, who inspects Brigitte’s wound. Murphy applies a leech, surreptitiously testing to see if a werewolf bit her. They are given a room that belonged to Wallace's son Geoffrey. That night Ginger is awakened by a voice and goes to investigate. Wandering the corridors she eventually finds the source of the voice, and enters a small, bolted unlit room; reaching out to a deformed boy, who turns and bites her as he flees.
Ginger and Brigitte try to leave the fort, but one of the men, James, confronts them. While Ginger and James are fighting, werewolves attack, killing one of their men. The sisters are led by Reverend Gilbert to an allegedly safe building, which actually contains a werewolf. The sisters run up the stairs chased by the werewolf, but the hunter appears and kills it. As Ginger and Brigitte are going to their room Ginger's nose starts to bleed; a sign that she is infected.
The sisters discover the boy who bit Ginger is Wallace's son Geoffrey. As Ginger sleeps he sneaks into the bedroom and wakes her. She tries to grab him but he gets away, taking a lock of her hair. One of the men investigates the noise and is killed by Geoffrey. The others find the body with the lock of Ginger’s hair beside it and drag Ginger away while James holds Brigitte captive. Wallace arrives, dismisses James, and makes a deal with Brigitte; her sister's life in exchange for their silence regarding his son. Wallace and Brigitte find Ginger at the doctor's, strapped to the examination table and held at gunpoint, about to be tested with a leech. When Wallace demands they release Ginger, Murphy ignores the order. Wallace shoots him dead, prompting the other men to leave.
Ginger is determined to kill the boy to lift the curse but when she finds Geoffrey, he is crying at his mother's grave. He escapes and is captured instead by the men. Wallace arrives and kills his son himself. The sisters' protection at an end, Ginger is forced to leave, and Brigitte goes with her. Desperate for a cure, the sisters go to the hunter's cave, Ginger killing their guide shortly before they arrive. At the cave, the hunter and Indian seer woman reveal the sisters' coming had long been prophesied and that the Red and the Black would decide the destiny of the werewolf bloodline. After Brigitte is put in a trance-like state she has a vision of her destiny; she sees the hunter attempting to kill Ginger, and then kills her sister herself. As Brigitte emerges from the trance she finds the seer is dead, killed by Ginger, who has fled. The hunter leads Brigitte back to the fort.
Back at the fort, Brigitte is taken prisoner. Gilbert goes to her, telling her to beg forgiveness to save her soul; Brigitte curses, spitting in his face. Gilbert drags her out onto the parade square, and prepares to burn her alive. He is interrupted by Wallace who runs Gilbert through with his sword before setting him on fire. James engages Ginger in a fight and she slashes his throat. As he falls to the ground bleeding to death, Ginger opens the gates and ushers in the werewolves. While the Hunter holds his own against them, Wallace is soon bitten and sets the fort on fire before killing himself. The hunter urges Brigitte to kill her sister; instead, Brigitte kills the hunter and flees with her sister. The film ends with only Ginger and Brigitte left alive, huddled in the snow. Brigitte then holds out her hand and presses a cut on it against a cut on Gingers hand, mingling their blood, and infecting Brigitte.