In New York City, an elderly woman, her granddaughter, and the latter’s Siberian Husky, Blaze, are walking through Central Park, looking for a memorial. As they seat themselves for a rest, the woman tells her granddaughter a story about Nome, Alaska 70 years earlier in the winter of 1925, shifting the film from live-action to animation.
Balto, a young wolfdog, lives in rural Nome with his adoptive family, consisting of a snow goose named Boris Goosinov and two polar bears, Muk and Luk. Being half-wolf, Balto is despised by dogs and humans alike. The only dog and human in town who are kind to him are Jenna, a purebred Siberian husky, and Rosy. He is in love with Jenna, but is often bullied by champion sled dog Steele, a fierce and arrogant Malamute, who also has a crush on Jenna.
One evening, all of the children are hospitalized with diphtheria, and Curtis Welch waits to get antitoxin. Severe winter weather conditions prevent medicine from being brought from Juneau and Anchorage by air or sea, and the closest rail line ends in Nenana. A dog race is held to determine the best-fit dogs for a sled dog team to get the medicine with heading to rendezvous with the train in Nenana and transport the antitoxin back to Nome. Balto enters and wins, but Steele exposes his wolf half, causing his disqualification. The team departs that night with Steele in the lead and picks up the medicine successfully, but on the way back, they end up stranded at the base of an icy hill, with the musher unconscious.
When this news reaches Nome, Balto sets out in search of them with Boris, Muk and Luk. On the way, they are attacked by a massive grizzly bear, but Jenna, who followed their marked trail, intervenes. The bear pursues Balto out onto a frozen lake, falling through the ice and drowning in the process, while Muk and Luk save Balto from a similar fate. However, Jenna has been injured and cannot continue on. Balto instructs Boris and the polar bears to take her home while he continues on his own. Jenna gives him her bandanna to wear. Balto eventually finds the team, but Steele refuses his help out of callousness and attacks Balto, only to fall off a cliff. Balto takes charge of the team, but Steele, refusing to concede defeat, spitefully sabotages Balto’s marks and the team loses their way again. While attempting to save the medicine from falling down a cliff, Balto himself falls.
Back in Nome, Jenna is explaining Balto’s mission to the other dogs when Steele returns, claiming the entire team, including Balto and Steele’s musher, is dead, using Jenna’s bandanna as fake proof and tells Jenna that Balto made Steele promise to look after her. Knowing that Balto would never say such a thing, Jenna sees through his lies and insists Balto will return with the medicine. Using a trick Balto showed her earlier, she places broken colored glass bottles on the outskirts of town and shines a lantern on them to simulate the Northern Lights, hoping it will help guide Balto home. When Balto regains consciousness, he is ready to give up hope, but when a polar wolf appears and Balto notices the medicine crate still intact nearby, he realizes, thanks to remembering Boris’ advice he told him earlier, that his part-wolf heritage is a strength, not a weakness. Balto rallies his confidence and drags the medicine back up the cliff to the waiting team. Using his highly developed senses, Balto is able to filter out the fake marks Steele created.
After encountering further challenges and losing only one vial, Balto and the sled team finally make it back to Nome. Steele is exposed as a liar, and the other dogs abandon him in anger, and refusing his pleads to explain. Reunited with his friends, Balto earns respect from both the dogs and the humans. He visits a cured Rosy, who thanks him for saving her. Back in the present day, the woman, her granddaughter, and Blaze finally find Balto’s memorial, and she explains that Alaska runs the Iditarod dog race over the same path that Balto and his team took. The woman, revealed to be an elderly Rosy, repeats the same line, “Thank you, Balto. I would’ve been lost without you”, before walking off to join her granddaughter and Blaze. The statue of Balto stands proudly in the sunlight.
While the movie was kid friendly and cute, it is not historically accurate.