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.
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.
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.
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.