The premise is that the "myths" have come out: gods, goblins, vampires, and more. Unfortunately, this does not result in a renewal of their worship but all of them being rejected by society. The town of Avalantis, Alaska is reserved for them and becomes a city with 50,000,000 people in it. I'm not sure if that qualifies as a city instead of a nation since even New York City is only eight million people. Really, I'm inclined to think that it should have been only 5 million people but Twin Peaks had 51,000 people despite having only three cops in it so what do I know.
The story follows the recruitment of a up and coming police officer named Jesse into an elite branch of the Avalantis police department called MORTAL. Jesse is a wee bit bitter because despite devoting herself to the APD, she was almost murdered by her partner. It turns out being an overachiever and scrupulously honest cop in a corrupt supernatural reservation doesn't win you any friends.
However, Jesse's devotion to the law is just what needed when a politically sensitive case drops itself on MORTAL's desk: the death of Greek God Hermes. Apparently, he overdosed on a drug that briefly restores divine power and exploded on a bunch of cops. Who gave him the drug, why, and how much more do they have of it? It's a fascinating combination of a very street-level story with an epic mystical one.
I was a big fan of supporting character Cassandra Cross who is a woman that ticks off Jesse in every single way. Whereas Jesse has devoted herself to being meticulous, efficient, conservative, and uptight (a bit like Exley from L.A CONFIDENTIAL), Cross is well-liked and laid back. There's also the fact that Cross doesn't mind being openly sexual and this plays into a lot of Jesse's internalized misogyny. Jesse has sacrificed everything to be the top cop she thinks herself to be and is annoyed that Cassandra is seemingly able to be one without having sacrificed a life.
This is not a particularly serious work but is very humorous with barista gods, party girl goddesses, and even a high priest of Cthulhu from Kentucky. I was a bit uncomfortable with the fact people from real religious groups (Buddha, Kali) had their figures under "myths" but M.K. Gibson books have about as reverence for anything as South Park. It's basically Brooklyn 99 with gods, magic, and fairies.
In conclusion, I got a lot of enjoyment out of this book. I think everyone who enjoyed his other books will enjoy this work as well. This is the perfect afternoon comfort food and if you like your stories crass, fun, and with a surprising amount of heart then you will enjoy this. This is a funny, Brooklyn 99-esque series that people who don't take their urban fantasy too seriously will greatly enjoy. If I were to recommend this book, I would also recommend the audiobook version narrated by both Jeffrey Kafer and Heather Costa. The Kindle and paperback versions are fine but the narrators add a special "oomph" to everything.