This could be labeled a YA, as Ess is only 14 when she decides to run away from boarding school. By the time she screeches to a halt at the end of the book -- thanks to train robbers, the Pinkertons and a bullet! -- she's worked with the Secret Service and saved President Lincoln's life (so he can run for a 4th term!) and worked for the circus.
So what's she going to do once she turns 17? Find out about her career as a Pinkerton when she runs into the BLUE LOTUS SOCIETY in September!