After her mother's sudden death, 12-year-old Juliana (Emma Tremblay) is forced to repair an awkward relationship with her father as well as deal with the impending bankruptcy of the family business: a fishing lodge on majestic Lake of the Woods. In a last-ditch attempt to save the lodge, Dad (Adam Beach) organizes a high-stakes fishing derby. Juliana is powerless to help until she finds a world record Musky lurking in the waters around the lodge. Juliana devises a plan to catch the beast and save the family business. When she seeks the counsel of an old Native Ojibway guide, she learns that this particular Musky is an ancient 'medicine fish' with a spirit-essence crucial to the survival of the lake, and all other Muskies. Will she capture the mythic beast and save the lodge? Or will she allow the Musky to live and sacrifice her home? What medicine does this Magical Musky hold?