Victory of Eagles is a Temeraire novel. Temeraire is a dragon in Her Majesty's Service, in an alternate history where dragons are just another weapon in the arsenal of most large nations. This is book five in the series. They should be read in order to be appreciated.
Temeraire and Captain Laurence have been convicted of treason and separated. Captain Laurence is imprisoned on a ship and Temeraire is exiled to the breeding grounds. When Napoleon manages to cross the channel and threatens London, Temeraire and her captain are freed to help in the fight to save England. This is another story, set in a pre-industrial age, when the world is threatened by war and dragons can be the difference between defeat and victory. Another hard to put down tale. Highly recommended.