Police Lt. Diamond is told to close his surveillance of suspected mob boss Mr. Brown because it's costing the department too much money with no results. Diamond makes one last attempt to uncover evidence against Brown by going to Brown's girlfriend, Susan Lowell.
After getting out of prison, Johnny Clay masterminds a complex race-track heist, but his scheme is complicated by the intervention of the wife of a teller (George Peatty) in on the scheme, the boyfriend of the wife, airport regulations, and a small dog.