Fourth in the series (Surrender to the Will of the Night, 2010, etc.) featuring an alternate-world 13th century, the era of the crusades—along with gods, demons, monsters and wizards.
That being said, Cook disdains any explanations or even hints that might help ease newcomers into the flow. The Aelen Kofer, or dwarf wizards, trapped the Old Gods in a space-time bubble. Fresh from his success in killing the worst of these, Piper Hecht, along with his allies (including his sister Heris, ancestor Cloven Februaren, and Ferris Renfrow, all wizards), intends to release them in controlled fashion—and either kill them or force them to bargain for their lives. The gods that survive this process, perhaps daunted to discover how little magic power survives outside their ancient prison, seem biddable, cooperative and trustworthy—but they rapidly grow bored and start getting into mischief. Elsewhere, an enigmatic four-armed woman with supernatural powers visits Brother Candle, Countess Socia and Bernardin Amberchelle and, even more mysteriously, bestows astonishing gifts on them. Despite the presence of real, tangible gods, belief in the One God is strong, and the armies of the Grail Empire are preparing for another crusade against Hecht’s former coreligionists, the Praman. Winters grow longer, the ice builds and expands. And, seemingly out of nowhere, Hecht conceives an urgent need to recover Grinling, a lost magic ring wrought by the Aelen Kofer. All this, in Cook’s capable hands, comes across as less derivative than it might appear in summary; his characters have substance, their conversations sparkle. What he doesn’t convey are any senses of urgency, what it all means, why it matters or how it fits into the context of the series.
Presumably, you have to start at the beginning, and readers looking for a lengthy, well-narrated, but rather shapeless immersion should do just that.