You don't have to be thin to feel small.
Donnie's life is unraveling. His parents' marriage is falling apart, and his sister is slowly slipping away in the grip of her illness. To top it all off, he accidentally starts a rumor at school that hurts someone he cares about and leaves him an outcast.
So Donnie does the only thing he knows how to do: He tries to fix things, to make everything the way it was before. Before his parents stopped loving each other, before his sister disappeared, before he was alone. But some things are beyond repair, and it will take all Donnie's strength to stop looking back and start moving forward again.