The Traitor's Game by Jennifer A. Nielsen
"Nothing is as it seems in the kingdom of Antora. Kestra Dallisor has spent three years in exile in the Lava Fields, but that won't stop her from being drawn back into her father's palace politics. He's the right-hand man of the cruel king, Lord Endrick, which makes Kestra a valuable bargaining chip. A group of rebels knows this all too well - and they snatch Kestra from her carriage as she reluctantly travels home. The kidnappers want her to retrieve the lost Olden Blade, the only object that can destroy the immortal king, but Kestra is not the obedient captive they expected. Simon, one of her kidnappers, will have his hands full as Kestra tries to foil their plot, by force, cunning, or any means necessary. As motives shift and secrets emerge, both will have to decide what - and who - it is they're fighting for." - Inside cover
This book enthralled me. I was so anxious to see what would happen to Kestra and all the people she met along the way that I jumped right into book 2 and then book 3. The whole series was great! I highly recommend it to anyone who likes YA Fantasy. There will definitely be things you don't see coming.