Watch FREE Pretty Little Liars on br br Pretty Little Liars - Season 1 - Episode 1 - Pilot br br Pretty Little Liars is an ABC Family network television series based on the Pretty Little Liars series of novels by Sara Shepard. br The series follows the lives of four girls — Spencer, Hanna, Aria, and Emily — whose clique falls apart after the disappearance of their queen bee, Alison. br br I.