Uprooted (2015)

"Agnieszka loves her valley home in a quiet village. But the corrupted Wood stands on the border, full of malevolent power, and its shadow lies over her life. Her people rely on the cold, driven wizard known only as the Dragon to keep the Wood's dark forces at bay. But he demands a terrible price for his assistance: every ten years, one young woman must be handed over to serve him without question. The next choosing is fast approaching, and Agnieszka knows--everyone knows--that the Dragon will take Kasia: beautiful, graceful, brave Kasia, all the things Agnieszka isn't, and her dearest friend in the world. And there is no way to save her. But when the Dragon comes, it is not Kasia he will choose."--Back cover.