Since I've watched the movie of the first book, the Lightning Theif a ton of times (and fell in love with it), I decided to move on to the next one.
It's starts with Percy's last day of the school year...for an easy summary:
Tons (literally tons that you'll forget the names and what it looks like) of monsters appear here and there.
+ Grover in trouble
+ Camp Half Blood in trouble
+ Thalia's tree (which is a new thing for me since it's not in the movie, at all) in trouble
+ Percy has a brother
+ Chiron says bye bye
+ Luke returns w/ pieces of Kronos (not in the movie too, it's Hades in the movie)
+ Bermuda Triangle
+ Brace Yourself (you'll get it once you read it)
+ a twisted, unexpected ending
= GREAT DEMI GOD ADVENTURE!
I would just like to say that, it would be more of a thriller if the summary (in the book) and the chapter titles aren't too revealing.