Wicked is the fifth book in the series “Pretty Little Liars”. In this book, four high school girls uncover secrets about their old friend, Alison DiLaurentis. In the seventh grade, Alison and the four girls Aria, Hanna, Emily, and Spencer were best friends. Alison disappeared at the end of seventh grade and was not mentioned until three years later, when the other girls separated and lived their own lives. But now, they started to uncover secrets that they never knew about when Ali was living.