Alison DiLaurentis, manipulative and vindictive "Queen Bee" of Rosewood Day, rules with an iron fist over her clique: Spencer Hastings, a perfectionist always trying to outdo her over-achiever sister and the only girl in the group to ever stand up to Alison; Hanna Marin, overweight and so desperate to be popular that she bends to Alison's will; Aria Montgomery, a former outsider; and Emily Fields, a competitive swimmer from an ultra-conservative family who are overbearing and overprotective. But before the start of the 8th grade, Ali disappears after getting into a heated argument with Spencer at a sleepover with the other girls and the group falls apart. Three years later, Aria, back from a stint in Iceland that left her feeling confident, beautiful, and more stylish than ever reluctantly returns to town to find former nerd Mona Vanderwaal and a newly-thin Hanna to be the new social leaders of Rosewood Day. Soon Aria begins an affair with her English teacher, Spencer falls for her sister's boyfriend, Emily is in love with the new girl at school, and Hanna not only shoplifts, but also makes herself throw up to stay thin. Suddenly a mysterious person called "A" threatens to reveal the girls' secrets from past and present, including ones they thought only Alison knew; and one in particular that the girls refer to as "the Jenna thing." Ultimately, Alison's body is found buried, under the cement in her former back yard, and the DiLaurentis family holds a funeral for Alison in Rosewood, "the only home Alison ever knew".