On his 11th birthday, Jackson is nervous about moving up to middle school where he knows he'll be bullied by older kids, so he makes his wish, "I don't want to grow up!" When his 12th birthday rolls around, he discovers his wish came he's still 11, and he’s starting fifth grade (again). At first, this is the perfect life. Jackson is the smartest kid in his class, the best on his baseball team, and the star of the school band. But after a few years of being 11, he realizes his life is passing him by. His little sister is suddenly his big sister, his former friends are driving, everyone else is growing older but he's still living the same fifth grade life. Will Jackson ever figure out how to grow up or will he remain Stuck?