Better Living Through Alchemy - Evan Peterson J.

Kelly Mun is a private detective... with an uncanny sense of smell. She runs Non-Linear Investigations with her cousin Critter, using psychic and esoteric methods to try to earn a living. When a mysterious businesswoman hires them to find the source of a deadly new street drug called bardo, Kelly's life gets even stranger than usual in this occult-noir Seattle. 

The monsters are incidental.