In the third novelization of the Hugo Award-winning Girl Genius webcomic, Agatha Heterodyne returns to her ancestral home, the town of Mechanicsburg, to claim her inheritance by convincing the artificial intelligence that animates her family's castle that she is, in fact, the new Heterodyne. But this presumably simple task is quickly complicated. An impostor claiming to be the legitimate heir appears. The Empire is convinced that Agatha is the person responsible for the Long War. And, perhaps most troublesome of all, the castle itself is insane.