During a costume party, guest Karen Powell goes into
labor and is rushed to the hospital by her husband Brian and their friends. The baby, named Jack, inexplicably looks full-term and healthy despite having been born in the 10th week of gestation. Medical exams reveal that Jack suffers from a unique condition that results in him growing four times faster than normal. Ten years later, at age 10, Jack has the body of a 40-year-old man. One day, four boys are lurking outside of his house, intrigued by rumors of a monster inhabiting it. Jack scares them away by dipping a
fake eye into slime and throwing it at them from his window. Jack has grown childish due to this secluded life, having socialized only with his parents and his tutor, Lawrence Woodruff, who suggests that he attend school. Jack's parents initially reject the suggestion, fearing that school could be traumatic to him, but they eventually agree. When he first attends school, Jack is rejected by most kids due to his appearance. His father encourages him by installing a
basketball hoop to help him learn to fit in. One day, a boy named Louis picks Jack for his team to play basketball, and they win against some bullies. After school, Louis asks Jack to pose as the principal to avoid punishment from his mother, Dolores. Afterward, they become friends and Louis invites Jack to a clubhouse with the other kids, enlisting him to get adult items for them. Jack develops his first crush on Miss Marquez, his teacher, but, when she rejects him, he becomes deeply saddened and collapses going down the stairs. At the hospital, Jack is revealed to have begun developing cardiovascular problems, a sign that he is aging. Realizing the dangers that it might entail for his health, his parents decide to withdraw him from school, which upsets him. Jack sneaks out of the house and goes to a bar, where he gets drunk, befriends a man named Paulie, and tries to hit on Dolores. However, he gets into a fight with an angry man at the bar, and both are arrested. Dolores bails out Jack and comforts him after dropping him off at home. He locks himself in his room and does not come out for weeks. Karen speculates that Jack realized the fragility of his life and is scared of facing the outside world again. Meanwhile, his friends continue to come to his house, hoping that he will come out and play, but he refuses. Finally, Louis lures Jack out of the house by bringing over the entire class, spending the day playing in the front yard. The next day, Jack decides to return to school. Seven years later, an elderly-looking Jack and his four best friends are at their high-school graduation. Jack delivers the
valedictorian speech, reminding those in attendance that life is short, and he encourages his classmates to make the best of it as they all head into the future. ==Cast==