Pretty Little Liars is an American teen drama mystery-thriller television series loosely based on the popular series of novels written by Sara Shepard. The show premiered on June 8, 2010 on ABC Family. After an initial order of 10 episodes on June 28, 2010, ABC Family ordered an additional 12 episodes for season one. These episodes began airing on January 3, 2011 and ended on March 21, 2011. The ratings success of the first 10 episodes prompted the book series to be extended beyond the initial eight novels.