A Tale of Two Castles by Gail Carson Levine

Newbery Honor author of Ella Enchanted Gail Carson Levine weaves a spellbinding tale about a clever heroine, a dragon detective, and a shape-shifting ogre.

Newly arrived in the town of Two Castles, Elodie unexpectedly becomes the assistant to a brilliant dragon named Meenore--and together, they begin to solve mysteries. 

Their most important case concerns the town’s shape-shifting ogre, Count Jonty Um, who believes someone is plotting against him. Elodie must disguise herself to discover the source of the threat amid a cast of characters that includes a greedy king, a giddy princess, and a handsome cat trainer.

Readers who loved Ella Enchanted and Fairest will delight in this tale of a spirited heroine who finds friendship where she least expects it and discovers that goodness comes in all shapes and sizes.