Defy, by Sara B. Larson, is a young adult fantasy just released January 7, 2014.
Alexa Hollen is a fighter. Forced to disguise herself as a boy and serve in the king's army, Alex uses her quick wit and fierce sword-fighting skills to earn a spot on the elite prince's guard. But when a powerful sorcerer sneaks into the palace in the dead of night, even Alex, who is virtually unbeatable, can't prevent him from abducting her, her fellow guard and friend Rylan, and Prince Damian, taking them through the treacherous wilds of the jungle and deep into enemy territory.
I'm a softie for books where the captain of the guard falls in love for the lady he's guarding (like Crown of Embers by Rae Carson); and that was my favorite part of this book: in delightful reversal, Alexa falls in love with the prince she's sworn to guard. The whole girl-as-a-guard thing was genuine. There were other parts of the book that didn't work for me, but those have been covered by many other reviewers. But this part definitely worked.
I received a digital copy of this book via NetGalley for my honest review.