A year after Alison Dilaurentis  went missing, her friends begin receiving terrifying messages that include information only Ali knew. But even after Alison’s body is found, the messages continue.Alison was the “it girl” of Rosewood High School. She took in the eccentric Aria Montgomery the good girl, Emily Fields; the fat girl, Hanna Marin; and the overachiever, Spencer Hastings.  Because of Ali, these misfits found popularity and friendship. However, the four quickly grew apart when Ali disappeared during one of their sleepovers.

The girls awkwardly reconnect when they discover that each of them is getting mysterious notes, emails, and texts from someone who signs the messages with a simple “A.” When they don’t follow A’s instructions, some of their secrets are revealed to each other and the community.