The circumstances surrounding Alison's disappearance continue to haunt Aria, Emily, Spencer and Hanna, as questions arise about the night she went missing. To complicate matters, Jenna's return to Rosewood makes the girls face an unpleasant past and an incident that sealed their friendship forever. Can the girls face what has taken place in their past, especially since "A" won't let them forget?

Meanwhile temptation is everywhere they look, as Aria tries her hardest to stay away from Ezra and Spencer won't shy away from her sister's fiancé, Wren.

The girls try to put an end to "A" by blocking unknown users in their e-mails and texts. Meanwhile, various surprises await them, including a gift from a potential love interest, unsolicited advice and unwarranted academic recognition.