The story follows four estranged friends—Spencer, Hanna, Aria, and Emily—whose lives are upended when they start receiving anonymous messages from "A", a mysterious figure who threatens to expose their deepest secrets after the disappearance of their clique's leader, Alison DiLaurentis. Three years after Alison vanished during a sleepover, the remaining girls have grown apart and are living separate, seemingly perfect lives in the affluent suburb of Rosewood, Pennsylvania, all while harboring major secrets.
