The Truth as Told by Mason Buttle, by Leslie Connor

Mason Buttle's life is hard: he struggles with a profound learning disability, is tormented by bullies, and lost his only friend to a freak accident on his family farm. The local police have been asking Mason about it since it happened, and now that another friend is missing, they're back with more questions. But Mason is sweet and resilient and utterly inspirational.
find it at the library
find it at the library