An aging thief, assisted by younger accomplices, steals a 31-karat, legendary diamond. The plan goes awry almost immediately when one of the accomplices wounds himself with a pistol belonging to the jewel's owner. The remaining thieves don't trust each other. Erskine and Colby oversee a multi-state manhunt, trying to cut off any way the thieves can either fence, cut or ransom the large diamond. Before the case concludes, much treachery will unfold.