Napoleon invades England! Obviously, at this point, the Temeraire novels have gone pretty far off the history of the actual Napoleonic wars, but that’s good, because they’d otherwise be way too predictable.
In the last book, Laurence was sentenced to hang as a traitor, for bringing the cure to the dragon plague to the mainland dragons (yes, even the French dragons). However, the generals and admirals have realized that in order to keep Temeraire around, even in the breeding grounds, they’ll have to keep Laurence alive, so he’s on a prison ship, just when Napoleon finally invades England.
Temeraire and Laurence have to find each other again, and then figure out a way to push back the French forces. The nice thing about having it be new history is that while you know they succeed (there are more books), you keep guessing until the end about how they’ll do it. Definitely a good read – I very much enjoy this series.