Gordon Smith (David Arquette) is a mailman who has never met a dog he couldn't handle until one day when he offers to baby-sit James (Angus T. Jones), the son of his beautiful neighbor Stephanie (Leslie Bibb). Goran thinks that Stephanie will return his romantic interest but she feels that he is an overgrown kid and circumstances force her to leave James with him.
In another part of town, FBI agent Murdoch (Micheal Clarke Duncan) is trying to find his runaway canine partner, Agent Eleven (Bob) who has escaped from protective custody. Because of Agent Eleven's drug detecting abilities he has a contract on his life from local mobster kingpin Sonny Talia (Paul Sorvino). Luckily, Agent Eleven is a lot smarter and faster than Talia's two henchmen, Gino (Joe Viterelli) and Arliss (Steven R. Schirripa), so they aren't having much luck tracking him down. They lose the dog's trail completely when the dog seeks refuge in Gordon's mail truck. James adopted the dog and names him Spot.
Gordon finds both the kid and the dog to be alot of trouble but he finally gets use to them. When the mobsters catch up to them at a local pet store, all heck breaks lose and Spot gets to show his stuff. Stephanie returns home to find her son and Gordon remarkably transformed and Agent Murdock has come to collect his dog.