Everyone has something to hide - especially high school juniors spencer, aria, emily, and hanna. Spencer covets her sister`s boyfriend. Aria`s fantasizing about her English teacher. Emily`s crushing on the new girl at school. Hanna uses some ugly tricks to stay beautiful. But they`ve all kept an even bigger secret since their friend Alison vanished. How do I know? Because I know everything about the bad girls they were, the naughty girls they are, and all the dirty secrets they`ve kept. And guess what? I`m telling.