Being a half-breed, Balto is ridiculed by both dogs and humans. His only friends in town are a little girl named Rosie and her red—haired husky named Jenna, whom Balto is in love with. He is challenged by the city's favorite sled dog Steele, a fierce and arrogant Alaskan malamute. That night, Rosie and all the children get diphtheria. Due to the harsh winter weather conditions, it is impossible to deliver medicines by air or by sea from Anchorage, and the nearest railway line ends in Nenana after the governor of Alaska in Juneau gives permission to transport the antitoxin by rail. Dog races are held to determine which dogs are best suited for the team that is supposed to deliver the medicine. Balto participates in the race and wins, but is disqualified after Steele exposes his wolf-dog origins. That same night, the team sets off, led by Steele, and successfully delivers the medicine. On the way back, conditions worsen, and the team that has lost its way finds itself in a difficult situation