The Stone Sky (The Broken Earth #3) by N.K. Jemisin (2017)
The Obelisk Gate, we learn that nobody in Essun's time knows that the Earth used to have a moon. Alabaster implores her to learn how to harness the power of the obelisks because the moon is in long orbit and rarely nears the Earth. But soon it will be near enough to the Earth that maybe it can be knocked back into the old trajectory. This is the crux of The Stone Sky - Essun needs to try to achieve this feat, which hopefully will end the Seasons once and for all.
But she is where we left her at the end of the last book: traveling from the destroyed community inside the geode to another place where they all hope to live. Unfortunately, they're going in the opposite direction of where Essun's daughter Nassun last was - not that it matters, because Nassun is traveling too. She is also learning to harness the power of the obelisks, but for a very different purpose. Also in this final volume, we get a really great back story - that of Hoa, the stone eater, back when he was....well, not a stone eater. This story reveals what caused the moon to be knocked out of its orbit in the first place.
There is so much great stuff in this book! I had been dying for the back story, and of course was anticipating the moment Essun would attempt to get the moon back to its rightful place. It was so tense though, since Nassun's plans were pretty opposed to Essun's and only one of them could be successful. Also, Essun was slowly turning to stone as Alabaster did in the last book, which is a side effect of harnessing the obelisks in this way. So she had to be very careful using her powers because each time she did, another part of her would turn to stone. She had to really pace herself here.
The relationships between characters in this series are complicated, and watching how they develop was one of my favorite aspects of the story. In a Season, many things are suspended and times are desperate, which means you really, really want your community as a whole to survive because your own life depends on it. Those who are commless don't last long. Survival is the most important thing, but it's a given that not everyone is going to survive. This necessarily affects interpersonal relationships and means that leaders often have to make very tough decisions for the good of their community. Essun was in rough shape while she was traveling, but knew she wasn't going to get much of a break. She also had a lot of tension with Ykka, the leader of the community Essun inadvertently helped to destroy. I also really loved the relationship between Essun and the stone eater Hoa. And of course, Essun and Nassun were headed for the same place at the end and they didn't really have an awesome mother-daughter relationship in the best of times. So, there was a lot going on here!
I may have mentioned this before, but this is the first time in a very, very long time that I have read a series start to finish, one right after the other. Surprisingly, I didn't feel like I needed a break at all (even though the story was so bleak!) and I didn't get tired of it or wish it would hurry up and be over. Generally I'm pretty impatient and always thinking about the next thing, but I was so invested in what was going on that I wasn't at all in a hurry to leave it. In fact, I'd love another visit to this place - after the things happened at the end of this book I really want to know what everything was like for everyone going forward.
N.K. Jemisin has a book of short stories coming out later this month called How Long 'til Black Future Month, which is one of the best titles I've heard in a while. Of course I'm already on hold for it, but I was very excited to learn yesterday that one of the stories takes place in the world of the Broken Earth series, so I will get to revisit it after all!