Silvers has repeatedly pushed his boundaries time and again with this world and the protagonists he's focused on, to the point where many would attest to the idea that he's well on his way to burning himself out creativity-wise. Happy to say that it's rather the opposite, instead stretching his ideas out and maintaining a stable plateau rather than forcing himself to higher jumps and more abrupt twists just to try and push the envelope further.
The story remains engaging and once again solidifies Callie Penrose as more than just flashier arm candy for his other central series protagonist Nate Temple, the ongoing chemistry between them being just staggered and reluctant enough despite all the heat between them to make it realistic given their individual wildly chaotic existences. Nate appears once again in this novel though I will admit Silvers is kind of pushing the credibility of his 'Oh I wasn't here because of you, happy coincidence ain't it?" logic to all their run-ins, both appearing in eachother's books very briefly but making huge impacts on things in the story. It could be his way of tempting readers to imagine how hectic a full blown team-up between them would run, but it also gives the impression that some parts of their stories need the other to function properly, something I believe Silvers has been trying to avoid to let them both stand alone as stronger protagonists, especially since Nate Temple has had the much longer build up to his story before Callie was even introduced.
The rest of the story holds up well though and throws in more twists and turns for the overarching plot of the series and world as well as numerous nuances for the characters themselves. The backdrop of the Vatican is unfortunately sorely underdeveloped given how much of the story takes place there, it feels like another wasted opportunity to dig a deeper foundation for the feel and setting of the world of the story. Rather instead the action takes precedence again which is welcome, but given how staggered some events are from each other it just feels like there was room to stop and look around a bit, so to speak.
It unashamedly ended on a bit of a teaser towards the previously noted full on team-up, and once again the timing of the novel is set a bit ambiguously compared to the timeline of the Nate Temple novels so it can be hard to tell how big a leap forward one of them is taking when showing up in the other's book.
Also "bear peyote" is now a thing, and I am definitely stealing that one for my own use in the future.