A con-woman has a nice business fleecing gullible tourists who want a genuine 'underworld' experience, but the tables are turned when one of her victims turns out to be less innocent than he looks. Dodging the city detective who knows her by sight and wants her to "go straight", she next sets her sights on a valuable diamond pendant; but when her elegant nemesis turns up at the scene of the would-be crime, a race begins to see who can carry out the con first.