This book started out with Thalia's tree being poisoned, and Percy Jackson, along with Annabeth and Grover, sets out on a quest to the Sea of Monsters to look for the golden fleece, which will supposedly cure the poison and restore the magical borders that protects camp-half-blood.
I think this is a great book if you have an afternoon where it's cold and rainy outside and all you want to do is cuddle with a blanket on your favorite armchair and read an exciting adventure book.That is, if you have already read the first book on another rainy day just like this. (Just throwing some hackneyed stuff in here to get the ball rolling...)
What I really liked about this book was that it keeps you captivated throughout the book, but it's also quite short, which means you could probably sit down and finish this book in one sitting, skipping the entire "Oh my god I have to go but I can't put this book down" episode. Unless, of course, you didn't have the luxury of the cold, rainy, afternoon mentioned above.
So overall, while this book is not the MOST AMAZING BOOK EVER, it is certainly worth your time, and I would recommend this book to anyone who likes adventures and fantasy.