Joanna Hayworth is elated to help settle the Parisian estate of Pearl Littlewood, the owner of Parfum d'Antan, a shop specializing in vintage fragrance. But when a mysterious note in the funeral guestbook suggests that Pearl's death was not an accident, Joanna's much needed vacation becomes a hunt for a killer. At the center of the trouble is a rare bottle of perfume, Lys Bleu—the Blue Lily.

Joanna's quest to solve Pearl Littlewood's murder takes her across the City of Light, from the gritty Goutte d'Or, where a collective of Senegalese seamstresses chat about life and love; to a bustling early morning flea market; to a late night rendezvous at a drag club in the catacombs. What secret does the Blue Lily hold, and how many people must die before it's revealed?