Set in Paris during the 1889 World Exposition, man-about-town Gregory "Monty" Meru and his capable cohort Tebley "Tim" Fatago investigate five mysterious deaths that confound the mundane methods of the Paris Sûreté. Schooled from a young age in the ways of the occult, Monty sets out to use his unique expertise to solve the unsolvable. He's even had cards made up! They read: Occult Death Investigation.

The intrepid duo's adventures lead them to encounter psychics, shape-shifters, sorcerers, ghosts, sinister secret societies, human sacrifice, cannibalism, bizarre suicide and something far worse ... all set against the backdrop of fin de siècle Paris. As a result, Monty is transformed from charming dilettante to scarred, seasoned professional.

But what Monty doesn't realize is that a very real evil is stalking him from the start. A darkness is gathering, one into which our hero is inexorably drawn. He learns that even in the world of spirits, there are rules... and limits. His odyssey culminates in a test of will and destiny as he wrestles with an evil that his own grandfather helped unleash.