The title of this volume, Agatha Heterodyne and the Sleeping City, was announced by Phil on Girl Genius Adventures. He also announced that he and Kaja would be taking a two month break and resume the main Girl Genius story on March 3, 2014. In the interim, Christopher Baldwin will be filling in by illustrating a story based on one of the Girl Genius radio plays.
The thirteenth volume of Girl Genius begins with...
The colors were done by Cheyenne Wright.
This volume has a single extra, a two-page Girl Genius short, short story. This story is untitled, but might be called, "Doink, or Agatha's Bad Hair Day".