The main theme of this book has become, that really the most knowledge they have is that they know nothing. The four girls trying to find out who murdered their best friend are very confused. Every time they seem to have a lead it is demolished. Also an anonymous person known as A keeps haunting them. A knows secrets about them that no one else but their best friend Ali knew. However it cannot be her. She is dead; they found her body! As the book keeps going they realize that everything they thought they knew has changed. Everyone they thought they could trust has changed as well. Really what Aria, Hanna, Spencer, and Emily want now is the truth. And as A seems to find out new stuff about their lives that even Ali didn't know they get worried. Also how does A seem to know more about them than they even knew themselves?