After seeing both movies, I thought the 3rd book would be entirely new content. However most of the books lends it's plot to the 2nd movie. It's mostly the part where Greg (the wimpy kid) has a crush on classmate Holly Hills. The other part is mostly his dad getting mad at his slacker behavior and threatening to send him off to military school. The 3rd book isn't as good as the first 2, but I still enjoyed reading it.