Nemesis

Anghara is daughter to a king. In all the world only one thing is denied to her—the secret of the Tower of Regrets. This ancient, mysterious structure is forbidden by law, and she knows she isn't allowed to enter it, but she cannot rest until she knows what it is. Finally, she sneaks away and learns, finally, why it is called the Tower of Regrets. Her discovery will reshape her world and her identity and saddle her with an enormous, sorrowful quest to restore what she has set free from the Tower.