Fairy Tales, book 2: The Black Swan Mercedes Lackey1999

As the only child of a powerful sorcerer, Odile Von Rothbart has studied the magical arts under her father’s stern tutelage all her life. Yet she feels only fear toward him. For considering his wife’s untimely death the ultimate betrayal, Baron Von Rothbart scours the land in the shape of a great bird of prey. His personal mission is to capture woman who arouse his wrath and inspire his rage for vengeance against all womankind. These poor souls he turns into swans—forcing them to spend their lives as beautiful but powerless animals who only regain their human forms briefly each night by the transitory light of the moon.

Yet though Odile is terrified of him, she has learned far more than her father, the baron, intended to teach her—both of the magical arts and of Von Rothbart’s idiosyncratic nature. And both as a woman and the guardian of his swan flock, her heart goes out to each and every young maiden ensorcelled by her vindictive father.

And then the noblest of Von Rothbart’s enchanted flock, the Princess Odette, finds the courage to confront her captor, wresting from him a pact which could lead to freedom for herself and all the swan-maidens. Knowing Von Rothbart will use all of his magical cunning to avoid honoring this pact, will Odile have the strength to face him in a final magical confrontation which, if she fails, will lead to her death and the murder of all in her flock?