Calvin Cambridge (LIL BOW WOW) is a young teenage orphan who's been living at the Chesterfield Group Home Orphanage with his friends, including Murph (JONATHAN LIPNICKI) and Reg (BRENDA SONG), and other kids such as Ox (JESSE PLEMONS), the resident bully. Run by Stan Bittleman (CRISPIN GLOVER) and Sister Theresa (ANNE MEARA), the orphanage tries to find homes for the kids, but has a hard time with Calvin and the rest of the older ones.
As luck would have it, Calvin suddenly finds himself in possession of some old, donated tennis shoes that Sister Theresa believes belonged to a famous basketball player in the past. When Calvin spots the initials "MJ" inside them, he wonders if they possibly belonged to NBA star Michael Jordan. Calvin's luck continues when he happens to run into Coach Wagner (ROBERT FORSTER) of the Los Angeles Knights who invites him and his friends to a game.
It's there that Calvin's seat number is picked in a raffle and he's chosen to play in a brief exhibition match of one-on-one with Knights star Tracey Reynolds (MORRIS CHESTNUT). While Reynolds isn't crazy about participating in the publicity stunt arranged by team manager Frank Bernard (EUGENE LEVY), he and everyone else are shocked when Calvin beats him with various shots, including a slam dunk that's all the more amazing since Calvin is only four and a half feet tall.
Nevertheless, Frank and a reluctant Coach Wagner sign Calvin onto their team, and are happy when they suddenly start winning and filling seats. With Calvin partnered with Tracey while on the road, the two become something of an odd couple pairing, but Tracey eventually begins to warm up to having the boy around him. As they take the team closer to the playoffs, Calvin must then deal with his sudden fame, various people who want to undermine his success, and his continual hopes that someone will eventually adopt him.