There are two levels to this book. First you have two brothers on a journey, and all of the adventures they come across - locust, pirates, kidnapping, thieves, etc. Then you have a story of the brothers themselves, each very different, yet bound together by their birth and their love for their dead mother. The elder lives only for books and theories but knows nothing of the practical world; the younger has little care for schooling but is street smart and savvy. They have to rely on each other to reach their goal of Beijing, and come to appreciate and acknowledge the other's strengths.
I will say that this book was very engaging and interesting, I read it with much enthusiasm. A great historical fiction adventure story, I'd recommend it for teens, but I'm sure adults would like it too, it's a great story about the Ming dynasty in China.