See Spot Run

A mailman, Gordon (David Arquette), takes in a stray bullmastiff, Spot, who turns out to be a trained FBI dog. Spot escapes from a witness protection program and hides in Gordon's mail truck, which also houses Gordon's 6-year-old neighbor, James (Angus T. Jones). As Gino and Arliss, two hitmen hired by a crime boss, try to kill Spot, the FBI intervenes, and Spot ultimately helps subdue the crime boss, Sonny Talia (Paul Sorvino), allowing him to be arrested. After the ordeal, the FBI lets Spot choose his new home, and he chooses to live with Gordon and James.