Henrietta Von Harmon works as a 26 girl at a corner bar on Chicago's northwest side. It's 1935, but things still aren't looking up since the big crash and her father's subsequent suicide, leaving Henrietta to care for her antagonistic mother and younger siblings. Henrietta is eventually persuaded to take a job as a taxi dancer at a local dance hall - and just when she's beginning to enjoy herself, the floor matron turns up dead.
When aloof Inspector Clive Howard appears on the scene, Henrietta agrees to go undercover for him - and is plunged into Chicago's grittier underworld. Meanwhile, she's still busy playing mother hen to her younger siblings, as well as to pesky neighborhood boy Stanley, who believes himself in love with her and keeps popping up in the most unlikely places, determined to keep Henrietta safe - even from the Inspector, if need be. Despite his efforts, however, and his penchant for messing up the Inspector's investigation, the lovely Henrietta and the impenetrable Inspector find themselves drawn to each other in most unsuitable ways.