Starvation and disease haunt the streets of 1820s Paris, while supernatural terror stalks the night. The once-famous police force is a shambles, its elite Bureau of Supernatural Investigations disbanded. Only Detective Inspector Elise Corbeau remains, spared by a shadowy protector for a purpose not even she knows. When charismatic cult leader Hermine Boucher is kidnapped, all fingers point to her ex-lover, inventor Maria Kalderash. But the further Inspector Corbeau investigates, the more suspects she turns up, until finally, the finger is pointing right back at the Paris Police.

Navigating a web of betrayal, hidden agendas, and shifting alliances, Corbeau must protect the innocent, bring the corrupt to justice, and escape the ever-growing list of people who want to see her at the bottom of the Seine. If she can do it, she just might save her job. And she may even find true love.