I Am Number Four- Pittacus Lore

I had heard a lot of good things about this book so I decided to read it, and it is now one of my favorite books.
This book starts with Number Three being killed. John Smith is Number Four. He's an alien from the planet Lorien disguised as a teenager. His guardian's name is Henri, also from Lorien. When John lived on Lorien, his planet was invaded by Mogadorians. They are also aliens that are hunting John and others of his kind. 
Everytime one of his kind is killed, John and Henri pack up and move to another place. This time, they go to Paradise, Ohio. At school in Paradise, John meets Sarah Hart. She's the popular girl, and she used to date a guy on the football team. Automatically John begins to like her. He also meets Sam Goode. He's a total nerd and he's obsessed with aliens.
It turns out that they lay low for quite a while, until John has to use his legacies (the powers that he gets from being part of his alien race) to save Sarah from a cruel joke that the football players set up. Sam definitely suspects John of being something different once he sees what John can do. In the end, John ends up having to tell both Sarah and Sam of his kind and how he came to Earth. There are many dangerous adventures that he and his friends have to go through, one of which in where he meets Number Six.
I didn't tell all that much about the book because there are a lot of parts that are better to actually read then to just be told about. Overall, I thought this book was really good and well written. I would recommend it to almost everyone. 
This book made me realize that people aren't always what they seem, and there is a lot more to a person than just the outside.