See Spot Run

A dog-hating postman can't resist the charms of a stray mastiff. What he doesn't know is that the pooch is the FBI's best sniffer dog, currently on a witness protection scheme to keep him safe from a drug dealer. As the gangster tries to find him to rub him out, FBI agent Michael Duncan Smith is also on his trail and the innocent postman finds himself caught in a battle between the two.