The Princess Curse by Merrie Haskell

Merrie Haskell’s middle-grade fantasy novel Princess Curse is an imaginative retelling of the fairy tales The Twelve Dancing Princesses and Beauty and the Beast.
 
In the fifteenth-century kingdom of Sylvania, the prince offers a fabulous reward to anyone who cures the curse that forces the princesses to spend each night dancing to the point of exhaustion. Everyone who tries disappears or falls into an enchanted sleep.
 
Thirteen-year-old Reveka, a smart, courageous herbalist’s apprentice, decides to attempt to break the curse despite the danger. Unravelling the mystery behind the curse leads Reveka to the Underworld, and to save the princesses, Reveka will have to risk her soul.
 
Princess Curse combines magic, suspense, humor, and adventure into a story perfect for fans of Gail Carson Levine.