Lan is the 7th son of a 7th son. Of course, he's also the 14th child in the family. And his twin, Eff, is the unlucky 13th child. In an alternative history of the United States, where steam dragons exist, magic is used for everyday chores, and Lewis and Clark never made it back, Eff is growing up with the knowledge that she is cursed and expected to become evil.
Wrede provides an interesting premise, an alternate United States where magic, but she's done this before, with the letter series she did with Carol Stevenson. And the setting, though with much potential, was lacking. I wanted to know more about the amazing creatures that were supposedly beyond the barriers and the lack of information about a steamdragon, why it was called that, what it actually looked like, etc was annoying. It felt jumbled mixing mythical creatures plus those extinct in our present day.
Eff's family relocates from their hometown to a Western post so her father can become a teacher of a magic university. All of the children learn magic at school, though mostly only a Avrupan (European) style of spell casting. An unorthodox day school teacher also introduces Eff and a few other kids to Asian and Aphrikan (African) styles. Her older sister runs off to marry into a group who believe magic is a crutch, but is shown to still be using basic spells, so there's not much of a sense of life in that community without magic.
Though I felt like I captured Wrede's intention, overall I was disappointed. Things split off in too many directions: animals, characters, and nothing felt fully developed. Years of time passed quickly and, while more realistic than total self realization in a week at the beach, the whole thing felt awkward.
It was, at best, okay.