Rosewood is a perfect little town. So quiet and pristine, you'd never guess it holds so many secrets. Some of the ugliest ones belong to the prettiest girls in town -- Aria, Spencer, Hanna and Emily, four estranged friends whose darkest secrets are about to unravel.

One year ago, Alison, the Queen Bee of their group, disappeared and the girls swore they'd never tell what really happened that night. They thought their secrets would bond them together, but just the opposite is true. Then again, who's to say what the truth is in Rosewood. It seems everyone in town is lying about something.

Now, as the mystery surrounding Alison's disappearance resurfaces, the girls begin getting messages from "A" saying - and threatening - things only Alison would know. But it couldn't be Alison. Could it? Whoever it is, they seem to know all the girls' secrets, and seem to be watching their every move. The girls are friends again, but will they be there for each other if their dark secrets come to light?