The play is based on the female writer Sara Shepard girl novel of the same name adapted from a youth idol TV series. Beneath the tranquil exterior of the town of Rosewood, there are many secrets. Three years ago, the four prettiest girls in town-Aria (Lucy Hale Lucy Hale), Spencer (Teri Ann Belisorio Troian Avery Bellisario), Hanna (Ashley Benson Ashley Benson) and Emily (Xue Mitchell Shay Mitchell) friend and school most popular girl Alison (Sasha Pieterse Sasha Pieterse) suddenly disappeared, the four vowed to keep a secret but the relationship drifted apart. Three years later, the four received a text message from mystery man A, knowing that they had hidden a secret that only Alison knew for a long time. Thought A was Alison, but the police found her body in Alison's backyard. The mysterious An is always a mystery. How will the four girls deal with all these changes?