Five months following the discovery that Mona Vanderwaal was the elusive "A" that had been creatively and relentlessly tormenting the four main characters, Aria Montgomery, Spencer Hastings, Hanna Marin, and Emily Fields for the past year. The first half of the season addresses the issue of whether or not Garrett Reynolds actually killed or was involved in the murder of the girls' former friend and queen bee, Alison DiLaurentis and who killed Maya St. Germain in the season two finale, while the second half deals with the reveal of another "A" and the fallout while the mysterious Red Coat stalks the girls.