Coconut Hero follows the story of Mike Tyson (not to be confused with Mike Tyson); a 16 year old student living in the Canadian town of Faintville. The film begins with Mike trying, and failing, to commit suicide. After surviving his suicide attempt, Mike soon finds out that he has a deadly tumor. Initially, the tumor appears as a godsend in Mike's mind as he becomes increasingly preoccupied with the desire and development of a mission to find a way to end his life. This mission is reinforced by his religious figure's encouragement for Mike to find a plan for himself and follow through with it.
After finding out about his tumor, Mike meets Miranda and his priorities in life change from his morbid preoccupation, to spending time with and learning about his new love interest. Soon after, Mike also meets his father; a figure that had been absent in his life until this point in time. Cynthia, his mother, objects to his father's sudden return, but becomes closer to him after learning that Mike has planned against getting surgery to remove his tumor: the only means of saving his life.
Mike becomes overwhelmed with the conflict between choosing to fulfill his wishes of ending his life versus his thoughts and feelings surrounding his new relationship with Miranda. These feelings lead Mike into making a spontaneous decision to run away with Miranda on a road-trip. After witnessing Miranda being struck by a car and suffering an unfortunate death whilst still on their trip together, Mike decides to get the surgery that will remove his tumor. Ultimately, Mike chooses life.