Gordon is a mailman who has never met a dog he couldn't handle. Until one day when he offers to baby-sit the son of his beautiful neighbor and soon finds himself with a new animal in his life: an FBI agent's drug-sniffing dog, who has escaped from a witness protection program with local mobsters in hot pursuit. When the runaway canine seeks refuge in Gordon's truck, it's the beginning of a wildly comic adventure that leads to some unexpected transformations for both man and dog.