This is the second book in internal chronological order of Marion Zimmer Bradley's Darkover series that I own, and I don't think I'm missing any intervening ones. The story is a set a long time after the events of Darkover Landfall (post) and Darkovan society has had ample time to forget their off-world origins. The culture that's grown up is pseudo-feudal in nature and heavily dependent on psychic powers to replace the technology that was impossible on this metal poor world. The aristocratic caste are the Comyn who are those with laran, their name for psychic powers. The Comyn have been breeding themselves for every more potent powers, and not just breeding but manipulating their genetics (using laran). The results have not been good in the long term and that's one of the primary themes of the book and the one the story is shaped by.
Dorilys is the Stormqueen! of the title. Her family's laran is to do with weather control and with sensing the electrical field of the planet, and Dorilys is born with a particularly potent form of it. She's the only and much coddled heir to Dom Mikhail Aldaran, in a world where a woman doesn't really inherit but her husband does. For most of the story she's on the cusp of puberty, which is the most dangerous time for a member of the Comyn - that's when their powers come into full force and this causes an illness called threshold sickness which can kill, and in fact did kill Aldaran's older children. Whilst she's the title character and the key element around which the story revolves, I don't think she counts as the protagonist - that's two men: her half-brother Donal, and Allart Hastur.
Donal isn't Aldaran's son, he shares a mother with Dorilys, but Aldaran loves him like a son. And one of the tensions in the story is that Aldaran would like Donal to inherit but it's not possible. Donal doesn't have very strong laran - he's only touched by this over-engineering of the Comyn by what it's done to his sister. Allart Hastur on the other hand is another victim of the project. He has a form of foresight, but he sees all possible paths into the future. So without great effort and self control all he sees is how everything could go wrong with a single misstep. A simple journey from one town to the next is a torture of nightmarish visions about falling off his horse, breaking bones, getting snowed in or out of somewhere etc etc etc. He's retreated to a monastery of the Christoforos (descended from the Catholic faith of some of the original colonists) where the ritual of life has a steadying influence on his thoughts. But circumstances and family duty call him out of there, and he ends up involved in the tragedy at Castle Aldaran.
One thing I like about this book is the way it's structured. Even the first time of reading it (I'm pretty sure) I knew it was a tragedy going in. And as you read it feels inexorable, inevitable, like a giant rock rolling down a path towards you. The juggernaut can't be stopped. And yet, just before the end there's a moment of peace where you suddenly believe disaster might be averted, and everything hangs in the balance for an instant before it all comes crashing down.
In contrast to Darkover Landfall I can see how Bradley is using this book to explore feminist themes and ideas. It was written in the 1970s - published in 1978 so presumably written a year or two before that. Notably this is just after Roe v. Wade (the landmark case in the US that legalised abortion), and I think there's a lot in this book that's exploring women's control over their reproductive health/ability. For instance: Dorilys and Donal's mother dies when Dorilys is born, and it later transpires that if there'd been someone better trained in laran present to ask advice from during the pregnancy she'd've known that carrying a girl child who had that laran ability to term would inevitably result in the mother's death. And the skilled laran worker would also be able to abort the fetus while it was still very very early in the pregnancy. Thus saving the mother's life. And given the tragedy that later befalls Dorilys as a direct result of her laran, then perhaps that abortion could be seen as merely hastening the inevitable for poor Dorilys. This isn't the only example - another character does abort a fetus that had early detectable poor combinations of genes, and there's also discussion of using laran to prevent conception altogether when an adult's genetics mean that no child of theirs will be born unscathed.
As well as thinking about women's control of their reproductive systems, there's a lot of discussion of love matches vs dynastic marriages vs sexual freedom that plays out in the story. Particularly from the women's perspective, but also the men's. And another theme is that patriarchy hurts everyone. Allart in particular is as much a victim of this system as any of the women - he gets more agency in how he deals with it, but he's as forced into his marriage as his wife is for instance. But in more subtle ways the other men are also victims - Damon-Raphael (Allart's brother and one of the antagonists) wouldn't come to his own tragic end if he hadn't been brought up to believe that being power-mad and paranoid was the way to play the game. (Allart is explicitly regarded as weird by his peers for not seizing any opportunity to snatch power that crosses his path.) And Aldaran's part in what plays out in Castle Aldaran stems from his desperation for a male heir. Mentions should also go to the messages that "eugenics is bad" and "power corrupts", which are shown throughout the story.
So there's actually quite a lot of meat there in this story, underneath the skin (or kinda poking through the skin, to stretch the metaphor somewhat). And much of it is still relevant today. I can't really recommend it as a book though, because my god it's rapey. Off screen in general, but there's at least one attempted rape of Dorilys, there's references to brides being drugged for their wedding nights (with aphrodisiacs), there's genetically engineered non-human "brainless" sterile concubines (who aren't quite brainless, so caught between being people and being animal and neither status makes the situation any better). And so on. You could perhaps argue that Bradley couldn't make the points she was wanting to make without writing her society that way ... but it's pretty relentless and makes for a reduction in enjoyment of the story for me. And it's only made more uncomfortable by the fact that Dorilys, who is the target of a lot of the generally rapey attitude, is a pre- or peri-pubescent girl for most of the story.