New York Times bestselling author Tim Green has written an unforgettable story—inspired by interviews with real-life cancer survivors and insider sports experience—showing a brave boy who learns what it truly means to be unstoppable.

"Absolutely heroic, and something every guy should read." (National Ambassador for Young People's Literature emeritus Jon Scieszka)

If anyone understands the phrase "tough luck," it's Harrison. As a foster kid in a cruel home, he knows his dream of one day playing in the NFL is a long shot.

Then Harrison is brought into a new home with kind, loving parents—his new dad is even a football coach. Harrison's big build and his incredible determination quickly make him a star running back on the junior high school team.

On the field, he's practically unstoppable. But Harrison's good luck can't last forever. When a routine sports injury leads to a devastating diagnosis, it will take every ounce of Harrison's determination not to give up for good.