Pretty Little Liars S2, E20

Four friends band together against an anonymous foe who threatens to reveal their darkest secrets, while also investigating the disappearance of their best friend.

Cast:Troian Bellisario , Ashley Benson , Lucy Hale , Shay Mitchell , Sasha Pieterse , Ian Harding , Laura Leighton , Janel Parrish , Tyler Blackburn , Keegan Allen , Holly Marie Combs , Chad Lowe , Lesley Fera , Tammin Sursok , Lindsey Shaw , Andrea Parker , Torrey DeVitto , Nia Peeples