New Year's Eve, 1929.

Millie is running the show at the Cloak & Dagger, a swinging speakeasy in the French Quarter, while her aunt is out of town. The new year is just around the corner, and all of New Orleans is out to celebrate, but even wealthy partiers' diamond earrings can't outshine the real star of the night: the boy in the red dress. Marion is the club's star performer and his fans are legion—if mostly underground.

When a young socialite wielding a photograph of Marion starts asking questions, Millie wonders if she's just another fan. But then her body is found crumpled in the courtyard, dead from an apparent fall off the club's balcony, and all signs point to Marion as the murderer. Millie knows he's innocent, but local detectives aren't so easily convinced.

As she chases clues that lead to cemeteries and dead ends, Millie's attention is divided between the wry and beautiful Olive, a waitress at the Cloak & Dagger, and Bennie, the charming bootlegger who's offered to help her solve the case. The clock is ticking for the fugitive Marion, but the truth of who the killer is might be closer than Millie thinks...