Jack is a precocious chimpanzee living at San Diego's Pueblo University where he works with Dr. Kendall (LOMAX STUDY) and is cared for by Darren (RUSSELL FERRIER), his somewhat mentally handicapped keeper/janitor. Although Jack is a favorite among the students who study his behavior and is supposedly a genius, he's not working out that well in the study. That, along with the recognition of his failing health has Dr. Kendall arrange for Jack to be sent back to the El Simian Nature Preserve to be with his simian family.
Unfortunately, Dr. Kendall dies before that happens. When Darren then overhears Dean Peabody (OLIVER MUIRHEAD) announce his plans to sell Jack to another university for medical testing purposes, he secretly puts Jack onboard a train headed for El Simian, telling him to get off when he hears that stop being announced. It's a long trip, however, and Jack sleeps through the stop, ending up at the end of the line in Nelson, British Columbia.
There, California natives Steven Westover (KEVIN ZEGERS) and his deaf younger sister, Tara (JAMIE RENEE SMITH), are trying to adapt to their new surroundings. Although their parents, Mark (PHILIP GRANGER) and Susie (INGRID TESCH), are loving and supportive, Tara isn't happy because she thinks no one likes her due to her disability and Steven believes his hockey days are numbered.
That's because the local Junior B league team, the Nuggets, haven't won a game in a long time and the players have adopted a defeatist attitude. With their best player and team captain, Pete (AARON SMOLINSKI), sidelined with an injury, the goalie Magoo (RAY GALLETTI) needing glasses, and other players, such as Moose (SHANE VAJDA), being more interested in roughhousing than winning, there's little Coach Marlowe (RICK DUCOMMUN) can do with the team, much to the chagrin of stadium announcer Willy Drucker (DAVE THOMAS).
That is, until Jack shows up. First secretly staying with Tara, the chimp soon makes his way onto the ice and proves his abilities as both a skater and scorer. After Coach Marlowe convinces the board of directors that a hockey-playing chimp will draw in the crowds and thus generate increased revenue, Jack takes to the ice and not only leads the team to victory, but also helps Steven and Tara fit in with their new surroundings and classmates.
When news gets out about Jack, however, Dean Peabody sets out to reclaim the chimp, causing Steven, Tara and everyone else to come up with a plan to allow Jack to play in the championship game and prevent Peabody from selling him to another university.