Naomi Novik's Empire of Ivory, fourth in her Temeraire sequence, ends up in a much more interesting place than I initially thought it was heading. Temeraire is a resolutely SFnal piece of work, for all that Del Rey is taking advantage of the dragons=fantasy stereotype, and from what we've seen thus far is a solid piece of worldbuilding, thoroughly in Aubrey-Matarin territory. Ms Novik clearly knows her Napoleonic wars very well, and the extent to which the story tracks the historical flow of campaigning had led me to expect that she would continue to hew to the grand sweep of events in our own timeline, with the dragons ultimately having no net impact major enough to derail the important milestones of Napoleon's rise and fall. This may still be the case; I find it hard to believe that she will abandon the chance to dramatize the advance to Moscow in 1812 and the succeeding events through Elba, or the Hundred Days and Waterloo. But during those stretches when continental Europe was quiet, I had assumed that Ms Novik would be taking us off to other parts of the globe, inserting interludes of drawing-room activity (in O'Brian's fashion as well), and otherwise spinning intrigues and side-plots that would not materially affect her ability to return to Europe when Napoleon again sets forth and the red-letter battles recommence; that her alternative history would remain conservative, rather than disruptive.
In this volume, however, we see her pick up hints she was planting as far back as Throne of Jade, at least, and start down a path that can allow her to be as disruptive as she likes while not interfering with the chance to pick up the European high-points fairly closely. Events in Africa still don't have to impinge on Europe, but give plenty of room for expansion; we've still had only hints of the state of the Americas, and almost nothing (if I'm remembering correctly) about the Colonies or the United States, which of course will let her go wherever she chooses with the War of 1812; and it looks as though she has a major set-piece brewing with one of Napoleon's major plans that was, in our world, never executed. She has also already solved the problem that gave O'Brian such difficulty, and Forester too: the inescapable fact that the drama in our history largely ends for a generation in 1815. O'Brian resorted to a most amusing soft-shoe when he reset the clock back a few years in the middle of his timeline, and Forester had the what-do-we-do-now? Admiral Hornblower in the West Indies, but Ms Novik, in contrast, may find that the fall of Napoleon is more of a liberation than a dropping of the curtain, freeing her to roam the globe and recast history moving forward with even more wild abandon...