Shortly after the war at the end of Divergent, Tris and her remaining family and faction escape to Amity, just outside the city gates. But then Tris learns that her family and the entire Abegnation faction died for something, something that Erudite is fighting to keep hidden. Tris needs to know what it is, why her family died, and so she embarks on a new quest. But what she discovers will change everything. 
 In some ways, Insurgent was better than Divergent, and in some ways it wasn't. It was better in characterization; Tris is a much more fully-formed person in this book, very self-aware and working to improve herself. I heard complaints about Divergent along the lines that Tris did everything to impress Four/Tobias (which I disagree with), but in Insurgent that is obviously not the case. She does much of what she does in spite of Tobias, and frequently tells him that if he doesn't like who she is, he shouldn't claim to be in love with her. While she considers his feelings whenever she makes a decision, she does not allow those feelings to get in the way of doing what she thinks is right. 
 However, there was something about this one that made me give it four stars instead of the five I gave Divergent. I think it was the pacing; so much of the important stuff happens in the last few chapters, while the first 3/4 of the book is buildup and setup for the big reveal at the end. Whatever the issue was, this one didn't keep me up reading til 2 AM the way Divergent would have were it not for that pesky work schedule. 
 One tiny nit-pick: the "handle" of a gun is called a "grip." Just sayin'. 
 Overall, I enjoyed this book a lot, and it was at least as good as, if not better than, Divergent, which is quite the feat for a second book in a trilogy. I find that the second book is usually a slump in storytelling and plotting, but this was a strong book in its own right.