This is a lovely little fairy tale. Celia’s father helped their country win the war against the neighboring Summerlings (they’re Fae), and gained great power doing so. Celia is the youngest, and the only girl. And when her beloved oldest brother renounces their father’s name, she curses him, not realizing that she has inherited the powers of sorcery in her mother’s bloodline. This curse kicks off a series of events, because the war is not really over, and only Celia and her two brothers have the power to end it completely.
I really enjoyed this – it’s a quick read, and it’s absolutely a fairy tale, but a nice twist on those tropes.