In the Hand of the Goddess: Song of the Lioness #2

Disguised as a boy, Alanna of Trebond becomes a squire -- to none other than the prince of the realm. But Prince Jonathan is much more to Alanna; he is her ally, her best friend, and one of the few who knows that she's really a girl. Now it will take all of Alanna's awesome skill, strength, and growing magical powers to protect him from the mysterious evil sorcerer who is bent on his destruction--and hers! Here continues the story of Alanna, a young woman bound for glory who is willing to fight against enormous odds for what she believes in.