Flawless - Book 2 of the Pretty Little Liars series
The Pretty Little Liars Series (PLL) revolves around a group of girls Emily, Aria, Spencer and Hanna who used to be best friends with a girl named Alison. Ali had a lot of secrets on them and used them to manipulate them, one day she goes missing and the girls go their separate ways until Book 1 when the mysterious A starts to dish on what she knows, the funny thing is that only Ali was supposed to know those things.
Flawless follows pretty much the same pattern as the first book, with A threatening the girls with their secrets and the girls trying to figure out who is it, not sure in whom they should trust. I can't say much on the plot and such because well, it's a mystery! but I will say that both A and the girls are getting angrier and it seems that with each book we are taking down one candidate for A (In the first book A was believed to be Ali who is later found dead).
I won't say who is it in this book but it still makes for a pretty interesting read.
P. S. I must point out that PLL is not a series you can read out of order, because things progress from one book to the next.