In the rowdy red-light district of Storyville, four players of the new music they call "jass" have turned up dead. When Creole detective Valentin St. Cyr begins to investigate, he discovers that every one of the victims once played in the same band, and the only one left alive has gone into hiding.

As he digs deeper, Valentin becomes convinced that a shadowy woman is the key to the mystery. His efforts to find her touch nerves, and soon Tom Anderson, known as the "King of Storyville," police lieutenant J. Picot, and even the mayor of New Orleans want him off the case. It's all the proof Valentin needs that there is something even larger and darker at the heart of this sordid business.

A riveting follow-up to the award-winning Valentin St. Cyr mystery Chasing the Devil's Tail, Jass journeys further into the bloody and seedy netherworld that is Storyville, New Orleans.