Based on the book by Scott M. LeRette with Susy Flory, "The Unbreakable Boy" follows Austin (Jacob Laval), a kid born with a rare brittle-bone disease and autism. But what makes Austin unique is his joyous, funny, life-affirming worldview that transforms and unites everyone around him -- especially his dad, Scott (Zachary Levi), who changes his life as he comes to see Austin not as the symbol of something broken, but the triumph of an indestructible spirit.