Of Grave & Glory by Kathryn Ann Kingsley

Emma Mather is having trouble telling friend from foe…and being wrong about whether someone is her ally or her enemy could cost her more than just her life.
The Candle has taken Gigi Gage as their prisoner, and Emma will do anything to save her friend from whatever torture Dr. Thaddeus Kirkbride is putting her through in the Arnsmouth Asylum. But even if Emma—and her trusty fire poker—can manage to free Gigi, she’ll have to avoid the clutches of the Idol, as well.

To say nothing about the Church or the man she loves, who is incrementally losing himself to the eldritch horror taking over his body.

Nowhere is safe. No one is safe. Not Gigi, not Rafe, and certainly not Emma herself.

Between the Dark Societies and the Church on the one hand and her increasingly complicated love life on the other, Emma finds herself surrounded by shadows at every turn. And she’ll be lucky if all that happens is that she gets eaten alive by Rafe and his new friends.

Because the other options might end the world.
And the clock is ticking.