I loved this book. I've been looking for a new fantasy series for a long time now, but I haven't come across anything recently that's caught my eye. I almost gave up on The Fifth Season too, in part because the narration is in second person, which I found jarring at first, and in part because Jemisin drops you in the middle of the action with little explanation and no hand-holding. It took me a few chapters to get into the story and figure out what was going on, but I'm glad I stuck it out because the plot and characters ended up being great. Despite what I just said, I think it's almost better to go into this blind, but I'll try to describe it without giving too much away.
The continent our characters live on, "The Stillness," is a post-apocalyptic hellscape. There is near-constant seismic activity that triggers a new catastrophe (called a "Fifth Season") every few centuries -- sometimes in the form of massive crop-failures, sometimes in the form of volcanic eruptions, sometimes massive earthquakes that destroy whole regions (she includes a helpful appendix of these disasters if you're curious). In this world, there is a group of people known as orogenes (or more derogatorily as "roggas") who have some degree of control over seismic activity -- they can "sess" earthquakes, and, with training, prevent them from being too destructive. But they're also powerful, extremely dangerous, and widely despised -- many people kill their own children when they discover what they are, and it's often a race against time to see if a Guardian (their mysterious and sinister keepers) can arrive to collect the child before the family or the community has killed them. The plot isn't chronological; it moves around from chapter to chapter in order to tell three stories at three points in time: 20-odd years ago, when a young girl is taken to the capital to be trained as an orogene; some 10 years after that when a mid-level orogene goes off on a mission with her senior to investigate a disturbance in a coastal community; and "now," in the immediate aftermath of the latest apocalypse, when we follow a woman who is struggling to cope with her son's murder just as the quake hits.
I'm not going to say that it's an entirely original idea, but I think the execution was solid and I loved the dialogue and cast of characters. There's no lack of action, but Jemisin also takes the time to dig into her characters' emotional lives, and after a while the use of "you" starts to fade into the background. There's a strong focus on discrimination, both in terms of how orogenes are viewed in society and in terms of the treatment of subordinate nations and peoples by the Sanzed Empire that has conquered the continent. A lot of fantasy is set in pseudo-Europe (and often just pseudo-England), so it was refreshing to read something more diverse, and there's a wide variety of representation in terms of race, gender, and sexuality throughout. I would give this 4.5/5 stars if that were possible, but since it isn't I've left it at 4. It wasn't perfect, but it was a very strong start to the series, and I look forward to starting the second book, The Obelisk Gate, which just released this September. I would definitely recommend this to fans of fantasy.