In 1993, Jerry Shepard is a guide at an Antarctica research base under contract with the National Science Foundation. UCLA professor, Dr. Davis McClaren, arrives at the base. He presses Shepard to take him to Mount Melbourne to find a rare meteorite from Mercury. Shepard decides that the only way to get to Mount Melbourne is by dog sled.
Shepard and McClaren make it to Mount Melbourne, but are called back to base camp due to an approaching heavy storm. McClaren begs for more time, and Shepard gives him half a day, which is enough time to find a fragment of the meteorite. En route back to base, McClaren slips down an embankment, breaking his leg and falling into freezing water. Shepard uses the lead dog Maya to carry a rope to McClaren and pulls him out. The two battle hypothermia, frostbite and near whiteout conditions as the dogs lead them home. Once there, the entire human crew is immediately evacuated, while the dogs are left behind. Certain that their pilot will return within days for the dogs, Shepard tightens their collars to ensure they cannot get loose and run away. Because of the harsh weather conditions, no rescue will be attempted until the next spring – and by then the dogs will be dead.
Back at home, Shepard tries to secure a plane to return and save the dogs, but no one is willing to finance the risky expedition. Five months later, Shepard makes one last attempt to get back. McClaren realizes the magnitude of his ingratitude and uses the remaining balance of his grant money to finance a rescue mission. Shepard acknowledges that there is almost no chance that any of the dogs have survived this long, but he owes it to his team to go back for them.
After being left behind, the eight sled dogs – lead dog Maya, Old Jack, Shorty, Dewey, Truman, Shadow, Buck, and the young Max, wait in the freezing conditions for Shepard to return. After two weeks with no food, Max snaps his collar and attempts to hunt seagulls. All the other dogs follow suit, except Old Jack, who is too tired and weak to follow, and remains tied to the chain. Some time later, Dewey slips and falls down an incline, where he is fatally injured. The team stays with his body until morning, but have to leave. In the blizzard, Max becomes separated from the group. Maya manages to lead the team to the Russian base, which is unsecured and full of food, while Max finds his way back to the American base, which is still locked and abandoned. Setting back out into the wilderness, Max finds the carcass of a dead Orca, but is driven off by a leopard seal. Maya and the team are nearby, and Max lures the seal away so the team can eat. It doubles back and attacks Maya, who is badly injured when it claps its reptile-like maw onto her paw. The team, now reunited, continue traveling. They are starving, freezing and exhausted, and eventually the injured Maya collapses into the snow. The dogs lie down beside their leader as the snow piles up around them. They have been on their own for nearly six months.