The mystery itself, the trill beneath and the scariness of the story I guess. Why, it hooked me then. Every time I watch its episode I couldn’t help but odor Sara Shepard, the author known for the bestselling Pretty Little Liars series of young-adult novels. In Pretty Little Liars Season 1 Episode 7: The Homecoming Hangover, Sara will have a special appearance in the episode as a substitute teacher at Rosewood High School.