Pretty Little Liars is an American teen drama mystery thriller television series developed by I. Marlene King and is loosely based on the novel series of the same name written by Sara Shepard. The series follows the lives of four high school girls whose clique falls apart after the disappearance of their leader. One year later, the estranged friends are reunited as they begin receiving messages from a mysterious figure named "A" who threatens to expose their deepest secrets. Since its debut, the series has received mixed reviews from television critics, but remained a relative success for ABC Family, garnering a large fandom.The series finale was viewed by an estimated 1.41 million viewers. It had the second-highest rating of any cable TV series that aired that night.Since the series premiere, Pretty Little Liars has remained popular. In 2016, a New York Times study of the 50 TV shows with the most Facebook Likes found that the show's "popularity is tilted toward women more than any other show in the data — over 94 percent of 'likes' come from women".The series earned its highest rated episode with 4.20 million total viewers, ranking among ABC Family's top 5 telecasts in adult viewers 18–34, total viewers and women viewers.The highest rated episodes include season one's finale, with 3.64 million, and season two's premiere and finale episodes, each yielding nearly 3.7 million viewers.The show stands as the most watched series on ABC Family, maintaining a steady viewership of over 2.5 million and currently standing as the only show to yield an average of over 2 million viewers.