As a matter of fact, I just went to the book store today to buy The Last Olympian. I believe it'll be a very good book because Riordan's writing is a masterpiece. It is the last book in the action-packed series and it is sure to be wonderful.
If you remember that in The Sea Of Monsters it stated about the prophecy when Percy turns 16 years old. My brother says that in The Last Olympian, it talks about the prophecy and what it does.