Another story from the Polyphonica series, though unlike Black's focus on the police (https://www.goodreads.com/book/show/1...), this seems to lean more on the goons' side.
A regular no-good broke guy living in a dilapidated apartment with no talent for playing music (certainly keen on subjecting people to terrible sounds however) one day gets involved in the silly plot of a group of spirits who want to dominate humans, and a shy pushover spirit somehow becomes roped into being his maid. Things get serious when a legendary stolen score turns up, and he tries to get hold of it for the money, unaware of the political machinations behind the scenes.
It's a certainly engaging story, you can't help but root for the kinda slimy guy and his get-quick-rich plan, and the handful of naive yet determined spirits entangled into helping him.