The story is extremely good. We get an unusual perspective on the Revolutionary Wars through the eyes of unlikely hero Phineas Button. As a baby, Fin's father named her Phineas, since he had really wanted a son, but was greeted instead with his twelfth daughter. On a trip to Georgia, he leaves his daughter at an orphanage in the little town of Ebenezer.
(Here there be spoilers) Fin grows up feeling abandoned. Who would want a tomboy like her? She thinks that she has finally found someone who cares for her when Peter, another orphan, proposes to her. But the day that he finishes their new house she kills six British soldiers who had demanded food of her. This puts her on the run and forces her to leave Peter and the orphanage behind. Eventually she finds belonging in a really unique group of people, namely, pirates. (Here end ye spoilers)
By far the best aspect of this book is the writing, as good as the story may be. The writing in this book is absolutely exceptional, and completely unlike anything else I've ever read. It's literally like reading poetry all the way through an entire book, but in a very good way. The author's descriptions and prose are just incredible. What actually led me to read this book was two quotes posted on Holy Worlds, and from those alone I purchased the book and read it. This is the sort of book you'll want to reread just for the excellent writing.
Unfortunately, this book has a few flaws, as no book is perfect. I'd say highest on the list would be Fin's lack of respect for authority. While she shows respect to Bartimeus, the cook who befriends her, she shows little or none to other figures in her life. This isn't condemned or shown as wrong. Also, the book contains swearing in minor degrees. Some may argue that this is period-appropriate, and that sailors will swear, but in my opinion it's unnecessary. Thankfully, the swearing isn't a huge part of the book nor is it ever shown as a good thing.
Overall, Fiddler's Gun is an amazing story with some of the best writing you'll find. Reading this book is definitely a real treat. Personally, I'm going to be looking eagerly for the sequel when it comes out in ebook form before the end of the year.