More episodes in the tale! Two, in fact, that aren't really connected overtly except in sequence. spoilers ahead for the earlier ones.
It opens with Agatha's having another adventure with the circus, full of drama. During a fight, the jagers from the last book show up and fight on their side, and attach themselves to the circus. And Agatha discovers the limits of the circus's willingness to act, and why.
After that, they go through another pass, where there's a prince they have had an unpleasant past with. The prince decides on a command performance, and makes a discovery about Agatha. So he invites her for dinner.
The rest of the tale involves being secretly descended from the half-legendary Storm King, a treacherous daughter, the discovery that the Geisterdamen are trying to atone for something, Gil's grieving (though he admits that he only had hopes with Agatha), Klaus's discovery when he tries to revivify Agatha, drugs in the wine, and much more