When two poker players fall out over a game of cards, one of the men winds up dead. A shoeshine boy who saw the murder flees the scene and Kane tries to find him before the killer can eliminate the only witness to the crime.
Major Clements asks Kane for his professional opinion on a device the retired army officer has created to trap the person stealing milk bottles from in front of his door. Kane is impressed; the device works - only it results in the Major witnessing the murder of a small-time card dealer by a gambling syndicate's goon.
