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, the return of Jenna Cavanaugh (recurring guest star TAMMIN SURSOK - Home and Away, The Young and the Restless) 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 as Aria tries her hardest to stay away from Ezra and Spencer won't shy away from her sister's fiancé, Wren (recurring guest star JULIAN MORRIS - 24, ER).