After the war, Izzy Umboto (a minor character from the first book) is given independent command and a mandate to keep the peace on the rim. She and her crew uncover a slavery plot.
Compared to the first book, this one is far more focused. There is a clear feeling of moving forward instead of flying about all over the place.
Note: Mike Moscoe is more well known under the pen name Mike Shepherd. The Society of Humanity series is set in the same universe as the Kris Longknife books, but several decades earlier.