When their best friend Alison mysteriously vanishes, four girls believe their secrets are safe forever. But when they begin to receive threatening messages from someone named "A," the truth may be only one text away. Filled with mystery, scandal, intrigue and nail-biting suspense, Pretty Little Liars is based on the best-selling book series for young adults from Alloy. Set one year after the disappearance of Alison, the manipulative and vindictive queen bee, the one-hour drama revolves around four 16-year-old girlfriends -Aria, Hanna, Spencer and Emily - who have lost touch with one another until each begins to receive mysterious messages suggesting that Alison is watching them and knows their most private details they are desperate to keep hidden. Suddenly, living in their picturesque suburban community is far from perfect as secrets, lies and betrayals threaten everything they hold dear. Even after Alison's body is discovered, the messages don't stop.