Appearance in the film
Shasta makes a quick appearance when Adam pretends he is a sled racer.
When Adam and Shasta see Jean George racing, Shasta remarks (with a bark) that they will be nicer than Jean George after Adam claims 'One day, that'll be us' (referring to Jean George and his sled dogs)
Shasta's next appearance is when he first meets the Buddies, whom the latter believe the former is a wolf. Shasta finds Talon and the latter teaches Shasta and the Buddies how to be sled dogs (although Talon denies it for a moment). Shasta forms up his team: Budderball and Mudbud at the back, B-Dawg and Buddha in the middle, and with Rosebud and Shasta at the front.
In another quick scene, Shasta is confronted by Francois and Philippe two huskies, who make fun of Shasta and the Buddies for how young they are. Afterwards, Bernie, a Saint Bernard, warns them how dangerous a sled race can be.
Later on, Shasta fulfills Adam's dream by revealing the sled team, much to the latter's glee, and participating in the dog sled race, but Jean George is in it too.
In the next scene Shasta appears in, Talon calls him to see the northern lights and tell him that she could be a great leader like his dad.
Later, the team manages to get to the first checkpoint without much difficulty. However, Jean George cheats by sabotaging the other sleds. Adam, Shasta and the Buddies reach an igloo, where they are greeted by an Inuit man.
The next morning, Jean George's sled team and Adam's sled team nearly bump into each other. When Adam gets injured, Shasta and the Buddies help him get back up.
Afterwards, Francois and Philippe get in trouble when ice beneath them shatters. Jean George stomps away, and Shasta, out of choices, goes to help them. Once Francois and Philippe are out, Jean George immediately resumes the race, with Adam's sled team right on their tail.
Adam, Shasta and the Buddies end up winning (with Jean George's team stopping after nearly abandoning them) and Shasta says goodbye to the Buddies when Buddy and Molly reunite with the Buddies and they go home via airplane.
Right before the credits, Adam can be seen sledding with Shasta and other huskies, and the words 'The End' appear as they pass by.