The Church probably isn't happy about that, but, hey, you can't tell Neapolitans to shut down the opera.
Conrad Scalese, librettist and atheist, has just premiered Il Terrore di Parigi, which is a hit, in more senses than one: the opera-house was struck by lightning. The Church definitely isn't happy about that, and Scalese's butt is about to be impounded (for heresy or whatever else the Inquisition can nail on) when he gets an offer which, under the circumstances, he can't refuse. It seems that King Ferdinand wants a miracle.
See, a decade or so previously, there was this volcanic eruption -- Mount Tambora. Devastated Indonesia, beat the crap out of Europe ("Year Without a Summer"). Ferdinand has evidence that this was caused by an evil operatic miracle -- a Black Opera, in analog to the Black Mass -- and that it was merely the test run. He is trying to put together a counter-opera.
I was diffident about this book at first, because our introduction to Scalese is his cranky theological arguments with everybody (up to and including the Inquisition). My problem here is that I am an atheist, and moreover an atheist in modern America, and moreover I'm not eighteen any more, which means none of this stuff is new to me. I've read all those arguments (back in my talk.religion.misc era) and I can skip them these days. Yes, it's a valid way to characterize history -- drop in someone who matches the reader, show first-person how they mismatch the times -- but the idea of a novel of the Great Rationalist Debate bores the snuff out of me.
That is not what this novel is.
This book is -- I'm going to regret this phrase, but what do we call over-the-top SF with starships blasting each other out of the skies as planets explode in the background? We call it "space opera". It comes out of the older idiom "horse opera". (Cowboys blasting, horses explode... yech.) Well, this book is opera opera. I'm sorry. It's unavoidable.
You have a hastily-auditioned group of opera stars. You have Scalese, the librettist, and the prickly composer Roberto Capiraso. (Who only avoids the label "prima donna" because this is opera and they have literal prima donnas to deal with.) You have the Gnostic secret society that wants to reprise Vesuvius -- this is not their ultimate goal, mind you -- who are therefore trying to sabotage every step of the counter-opera. And you have a deadline, which is six weeks away. Commence the rehearsal insanity. The good kind of rehearsal insanity, with everybody playing at the top of their game, and then higher.
(You also have men singing the roles of women, women disguised as men, castrati singing women disguised as men -- frankly the whole thing is so Mary Gentle that I'm surprised she didn't take up opera twenty years ago.)
Emotionally, this thing pulls out all the stops right at the start -- on high-tension artistic temperament alone. It then adds a steady stream of emotional time-bombs: ambushes, betrayals, secret relatives, secret relationships, extremely public arguments, feuds, fires, ghosts and zombies. And it winds up (this is merely the predictable part of the denoument) with an opera performed in the middle of a volcanic eruption.
Why Are You Not Reading This Book.
It is rare, at my advanced age, that a story moves me to a ceaseless, subvocal expostulation of "Holy crap. Holy shit. Did she just...? Is she going to...?" Because Gentle goes there. Wherever "there" is. Then the next plot point comes up, and she goes there too, turned up to eleven. There must have been a point where I might have fallen off the train -- lost my sense of belief, and then the whole enterprise would have turned ridiculous -- but I never hit that.
I think this is not a perfect book. Chunks of the beginning and ending are too talky. I'm not sure if (spoiler cameo) really needed a walk-on role. But if it is too talky, it is the enthusiastic chatter of the true fan -- the opera fanatic, here -- who wants to convey the wonder of it all. I am always a sucker for that. And, really, how could you leave (spoiler cameo) out?