Has the same feel as Graceling - a world that has many similarities to our own, with the exception of a few "gifted" creatures or people. Titled as a "Companion of Graceling" there is only one character who exists in both worlds. There is the same adventure, struggle for self identity, and finding of true companionship/love.
A subtle theme runs throughout the book -- we are all responsible for our own behavior. As family relationships are discovered the source of certain traits become known, the absence of others characteristics are highlighted. The idea that we all have choices, regardless of our past or present circumstances, could be a great discussion starting point with teens.
Cashore's writing is stronger in this book, she relies less on convenient coincidences to tie up lose ends. There are a few awkwardly worded sentences that hint at poor editing, but on second look they could be attributed to character personalites.