In the Labyrinth of Drakes is so full of squee. That’s a technical term.
In this book, Tom and Isabella are shipped out to Akhia to work on a breeding program for dragons, in order to supply the army of Scirland with dragonbone for caeligers equivalent to those made by other world powers. So there’s one thread of plot whereby Isabella investigates the breeding of dragons, including a trip into the desert to find where they actually breed, and perhaps even witness a hatching.
Of course, we’re in Akhia, so there’s another thread to the plot as well: Isabella re-encounters Suhail, though his family disapprove very much of his association with her. Nonetheless, they find ways to speak to each other, and Suhail eventually accompanies her on her journey to the Labyrinth of Drakes, an area in the desert full of Draconaean remains and potentially untouched sites to delight the heart of any archaeologist.
There’s the personal plot, in which we finally discover who will turn out to be Isabella’s second husband (a fact which is a bit of a tease through the previous books, but obvious in retrospect), and then this intertwines with Isabella’s journey of scientific discovery and Suhail’s archaelogical pursuits. Overall, it’s very satisfying and not a bit wasted.