Pretty Little Liars is a series of young-adult novels by author Sara Shepard, beginning with 2006's initial novel of the same name. The series follows the lives of four girls – Spencer Hastings, Hanna Marin, Aria Montgomery, and Emily Fields – whose cliquefalls apart after the disappearance of their leader, Alison DiLaurentis, in the summer after 7th grade. Later, when the girls are juniors in high school, they begin receiving various messages from someone using the alias "A" who threatens to expose their secrets.
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