Discworld Noir (1999)

Ankh-Morpork is a city surrounded by darkness, where the cold river Ankh flows, where it always rains, and where dwarves and trolls co-exist with secret societies, religious fanatics, stupid police captains, and bar pianists. It is also where a bitterly sarcastic sharp-eyed private investigator named Lewton tries to earn a living solving bizarre cases. A mysterious woman named Carlotta hires him to find her lost lover. Wandering through the dark city and gathering evidence, Lewton has to solve the case, confront a sinister conspiracy, and once again become torn between love and despair.