This is probably my favourite book of all time (yes, yes I have read Harry Potter and as much as i like it, this is a much more superior class of storytelling). I have read and re-read my copy of Moonfleet so many times that it is now severely battered. I'm 18 and not really in the habit of reading old fashioned-type things, but trust me this is a really fab story.
It's about a young lad called John Trenchard who lives in the village of Moonfleet. One day he accidentally discovers a vault/tomb by the local church. He finds himself in a smugglers' den and becomes mixed up in their dealings. There is also the legend of Blackbeard's diamond and a mysterious locket discovered in the dead man's coffin. John and his father-figure Elzivir are forced to leave the village and go on an amazing adventure which never lacks in excitement. There are smugglers, prisoners, theives, guns, treasure, capture, escape, death and even a bit of romance - everything you could ever want.
I really love the writing style of this book too- it is over a hundred years old so some of the language is dated but I personally think that it added to the atmosphere of the story. Definitely do not be put off. I also like the fact that it is written in the first person as it makes you feel a lot closer to the main characters - especially near the end of the book.
To sum up: it's an AMAZING book. So buy it!