A contemporary fantasy that opens in Hell. . . .
Myrrh is praying, and the fire spirit Aidan baits her and talks of a strange thing. When they go to see it, they face a demon hunt. Also, they find a Demonsgate, which would unleash horrors in the mortal world.
Meanwhile, back in the city of Intrepid, Detective Church is staking out a graveyard with her partner Tom. It's been twenty-one years since the Dark Day when werewolves and vampires and other horrors erupted into the world. She's disgruntled after inability to bring charges against various magical crooks. In particular, an annual serial killer. . . .
And when the magic turns out larger than expected, capturing both of them and offering them as a sacrifice, it's disrupted by a woman with white hair and a red-haired man who can throw fire. Then the woman cures her partner's injury.
It involves a case that was officially considered closed, a vampire dying by misadventure, a priest who gets teary-eyed at the sight of Aidan but has to be told his name by Myrrh, patron saints, Detective Church trying to piece together stuff about Aidan, a couple of buildings burning down, a lawyer being scared off, and more.