The series is a modern retelling of 1001 Arabian Night, in which protagonist Shahrzad agrees to become the wife of the murderous Khalid the Caliph with the intent of killing him before he kills her on the dawn of the day following their weather. But once in the palace, Shahrzad finds the situation is more complicated, and even finds herself falling for the man she thought she hated for having married and then killing her best friend.
The second book gets deeper into the alliances and conflicts between different tribes in this early Persian world. As is common in YA novels, there are star-crossed lovers and love triangles and unrequited love and lots of love drama in general. There is also another common element of magic in this ancient world. However, the magic is more of a decoration than the main trust of the plot. Rather, the story concentrates on familiar and all-too-human issues: bravery and betrayal, selfishness and sacrifice, and whether one should follow one's family or follow one's heart.
It is a lovely, exotic world that is fun to lose oneself in. There are also some strong and well-rounded female heroes. Like most princess stories, they are all devastatingly gorgeous, but they are also clever, caring, and courageous. This ends up being a great "girl power" book, featuring a minority culture that we Americans should probably appreciate more than we do.
Plus, kudos to the author for telling the story in two books and not trying to stretch it out to the seemingly-inescapable trilogy in YA series. Although the characters all have flowing dark hair, the length and pacing of this book seemed to me, like Goldilocks, to be "just right."