Get ready for more twists and thrills as season four of PRETTY LITTLE LIARS begins in the moments following the shocking season three finale and the girls strive to make sense of the mysterious 'Red Coat' and what plans he or she may have in store for them. Based upon the book series by Sara Shepard, PRETTY LITTLE LIARS revolves around four teenage girlfriends: Aria (Lucy Hale), Emily (Shay Mitchell), Hanna (Ashley Benson) and Spencer (Troian Bellisario): who lost touch with one another after the mysterious death of a friend, Alison (Pieterse).