The Elemental Masters - The Cyprian

Elena, having lost her father, must rescue herself from her evil stepmother, a Master of Water, who has bespelled her brothers into swans. She is left without home or protection by her father's villainous widow, who plans to regain her wealth by selling Elena to the highest bidder.

Alone, Elena must not only find a way to save herself, but to reverse the spell that has transformed her brothers.

The latest in Mercedes Lackey's Elemental Masters series is a stand-alone romantasy based on Hans Christian Anderson's "The Wild Swans".