When a rare dragon egg intended for Napoleon is taken from a captured French ship, the British crew is excited over the prize money they'll receive for delivering it. But when the egg threatens to hatch before it can be delivered, they realize that the only way to keep the dragon's service for England will be for one of the ship's officers to bond with the hatchling. Captain Laurence gives up his naval career to partner Temeraire, only to learn that life in the secretive, slightly disreputable Air Corps will be a difficult adjustment for one who wasn't raised to join it.
This book was really entertaining. The fantasy-influenced version of the Napoleonic Wars is a great setting, full of an interesting blend of real and imagined detail. Temeraire is enchanting, and it's fun to watch Laurence react to the unconventional aviators after the years he spent in the stuffy, proper Navy.
There is a bit of suspension of disbelief required when it comes to the mechanics of using and supporting dragons. But if you require a high degree of realism to enjoy a well-written fantasy novel, then I think you may be reading the wrong genre.