Book 4, picking up speed so that the volumes are more like divisions in a single story. Serious spoilers ahead.
Like, after a prologue with Algonquin, it opens with a scene of Bob with his newborn niece, and the Black Reach . And after a council scene where Ian and Julius refuse to unseal Bethesda until she makes an agreement to not undermine them, they discover that Bob killed Amelia -- Katya tells them, delivering the news that Svena has therefore broken their alliance. Shortly thereafter, Chinese dragons arrive, and what happened in China with Chelsie starts to unfold.
Meanwhile, Marcie, still dead, talks with her father and learns something about Amelia's death.
The story unfolds. It involves Algonquin's reason for boosting the DMZ; how to become a Merlin; Raven's justifying a means of doing some magic by his being a scavenger; Fredrick's insistence on serving Julius in gratitude; luck good and bad; a mother dragon who tells her son something in the worst possible way, on purpose; and more.
There's a truly horrifying realization where I put together Bob's official titles and some revelations in this book.