Cornelia Funke 
Fearless 

After saving his brother, Jacob Reckless faces death from the fairy’s curse burning in his heart. In search of a cure he returns to the Mirrorworld, where he is reunited with Fox, a beautiful shape-shifting girl. He has one more chance: a golden crossbow, with the power to both save and destroy life, buried in a dead king’s tomb beneath an invisible palace. Jacob must cross continents, face monsters and men — including a dangerous rival — and learn what it means to stay alive.