After eight-year-old Kevin Mason's mother abandons him, he takes refuge in his fantasy of becoming Knuckles McGraw, a tough cowboy roaming the plains on his legendary horse, Burlington Northern. But instead of riding the range, Kevin is stuck in a foster home with a pierced and tattooed teenager named Ice and a mute girl named Breezy.

While he waits to be claimed by the father he barely remembers or the mother who left him a good-bye note in his lunchbox, Kevin (aka Knuckles McGraw) tries to communicate with Breezy, learns to get along with his bunkhouse-mate Ice, and discovers that memories can be as deceptive as family secrets.