Bright Dawn, a young Eskimo woman, lives in the remote coastal village of Womengo on Norton Sound in Alaska. Her father, Bartok, is the village's most respected hunter, known as the
an-yai-yu-kok, the one everyone listens to. Women never hunt in their village, but Bright Dawn has driven her father's sled to the sea ice for two winters, ever since her brother was killed when a harpooned seal dragged him into the sea. She chooses Black Star to lead the family's seven sled dogs. Black Star is pure white with a black star on his forehead and ice-blue eyes, part wolf through his father's bloodline. Bartok dislikes the dog's stubbornness, but Bright Dawn loves him for his willfulness and intelligence.
One November, while Bartok waits by a seal breathing hole on the polar ice, the ice bridge connecting the shore to the floe breaks apart. Unable to find her father in the blizzard, Bright Dawn lets Black Star guide the team home through the
eewoonucks, massive ridges of polar ice along the shore. The village searches, and hunters eventually carry Bartok home alive but with a badly frozen right hand. Dr. John Evans amputates all the fingers except his thumb.
Bartok's hand heals, but a deeper wound remains. He shuts the curtain against the sea, eats little, and trembles whenever ice crashes onshore. Dr. Evans diagnoses him with a phobia and recommends the family move to Ikuma, a settlement on the Yukon River, 40 miles inland. Mary K., Bright Dawn's mother, looks back sadly as they depart. Bartok does not.
In Ikuma, Bartok finds work as a watchman while Bright Dawn attends school and begins racing dog sleds. She and Mary K. gradually persuade Bartok to race too, and he becomes passionate about it, winning multiple races. Ikuma is a checkpoint on the Iditarod, the famous 1,179-mile dog sled race from Anchorage to Nome. Bill Weiss, president of the Empire Canning Company, and Frank Gibson, owner of the Gem Café, propose sponsoring Bartok for the next Iditarod. He agrees, and they hire veteran musher Peter Avakoff to train him.
During a December training run, the sled crashes into a tree, cracking Bartok's left shoulder. With their investment at risk, Weiss and Gibson are alarmed. Bartok proposes that Bright Dawn run the race. The sponsors object that she is too young, but she corrects them: She has graduated and is 18 years old. After two days, they confirm her entry. She trains with Avakoff and 14 dogs, then flies to Anchorage.
In Anchorage, Bright Dawn prepares for four days, organizing gear and food. She meets Oteg, a veteran Eskimo racer who advises her to start slow, emphasizing that the race is won by thinking. On race day, 69 drivers start. Bright Dawn paces herself, and Oteg catches up, pleased she listened. On the trail, she glimpses a pack of wolves led by a white leader. Black Star halts the team and howls with the wolf, their voices blending. Oteg attributes the wolves to King Raven, a trickster figure from Eskimo mythology.
On a treacherous descent near Happy River Gorge, Bright Dawn finds fellow racer Katy Logan's sled overturned at the edge of a bluff. She untangles Katy's dogs and rights the sled. At Rainy Pass, the marshal freezes the race for two days due to severe weather. Oteg builds an igloo. When the freeze lifts, Katy quits and gives her lightweight sled to Oteg, who passes it to Bright Dawn.
Beyond the pass, a bull moose chases the team, brushing dogs off the trail with his antlers. Bright Dawn frees the dogs from the towline, and Black Star leads them in bringing the moose down. Sky, one of the team dogs, is badly hurt. At the next checkpoint, Oteg urges Bright Dawn to leave immediately, but she insists on waiting to send Sky out by plane. Oteg leaves without her. She catches and passes him, resolving to rely on her own judgment.
Bright Dawn pushes hard for the halfway point, the ghost town of Iditarod, and arrives first to win $2,000 in silver. But the grueling trail exhausts her. Beyond Shageluk, thin ice breaks and the rear dogs and sled plunge into a river; Black Star and the front dogs pull everyone out. At Eagle Island, Oteg arrives with three injured dogs and his lead dog dead from a moose attack. Bright Dawn carries his injured dogs to the next checkpoint, Kaltag.
Camping near Kaltag, she sees the white wolf clearly: the same pure white coat as Black Star's, the same ice-blue eyes and black blaze on his forehead. She realizes Black Star must be this wolf's son. She ties him securely, but he gnaws through his rope and disappears with six of her dogs. After an hour, Black Star returns on his own.
With only seven dogs, Bright Dawn passes through Ikuma to a hero's welcome. Her father and sponsors urge her to leave during a storm while other drivers sleep. She discovers that Gibson has secretly added one of his dogs to her team, but knowing this violates the rules, she unhitches it and departs into the blizzard. At Shaktoolik, the trail crosses Norton Sound, the same sea ice where her father nearly died. A heavy whiteout blankets everything. Knowing whiteouts can last for days, Bright Dawn drives out while other drivers wait. She becomes separated from her team in the featureless white but stays still until Black Star finds her.
Before she can reach shore, the ice breaks. Bright Dawn is stranded on a small drifting island of ice, surrounded by open water and moving toward the Bering Sea. She makes a flag and flashes her headlamp, but more than 30 teams pass without seeing her. A plane drops food and a note promising help, but no one comes. At nightfall, she finds a skiff beached on the ice shelf. Bartok stands beside it. He has sailed through the ice-choked waters that once left him paralyzed by fear to rescue his daughter. He wastes no time, insisting she is not finished until she crosses the finish line.
They return to Womengo, where Bartok gathers the courage to enter the home he fled. He repairs her equipment and breaks trail through deep snow toward the next checkpoint at Koyuk. He offers her a bear-claw charm for protection. She hesitates, but takes it.
From Koyuk, Bright Dawn races toward Nome through fierce storms, losing time to a wrong turn at a fallen trail marker. She finds and fixes the marker, then pursues a gray-haired woman musher. Black Star lunges forward and brings them even, but he swerves to nip the other team's leader, costing precious seconds. They cross under the Iditarod Arch just behind the woman, finishing last.
Bright Dawn's parents and sponsors await her beneath the arch. At a banquet, she receives her $2,000 in silver, a surprise $2,500 Sportsmanship Award for helping other mushers at personal cost, and the red lantern, the traditional prize for the last-place finisher. Weiss reminds her that 36 of the 69 starters never finished. Her mother suggests she use the money for college and return to help Eskimo children caught between two worlds. Bartok plans to return to Womengo and the sea he once fled. The next morning, Bright Dawn declines a flight home and drives the sled herself, reflecting that she is not the same person who left Ikuma weeks ago. She does not yet understand how she has changed, but she feels it deep inside.