Pretty Little Liars follows four estranged best friends who are reunited one year after their best friend and queen bee of the group, Alison, goes missing only to discover they are receiving messages from an anonymous 'A' who knows all their secrets. The drama stars Lucy Hale (Privileged) as Aria, Troian Bellisario (Navy NCIS) as Spencer, Ashley Benson (Bring It On: In It to Win It) as Hanna and Shay Mitchell as Emily. (Source: ABC Family)