Spencer learns about Paige's shocking past with Ali, but will Emily listen to what her friends have to say?; Aria feels she has to help Ezra move on from his past.

Emily is caught in the crossfire as Maya's murderer is revealed; The liars are betrayed by someone close to them.

Trick or treat? The Rosewood Halloween Ghost Train becomes one killer party in this special Halloween-themed episode. Plus, Adam Lambert performs.

Radley Sanitarium gives Mona a clean bill of health, and she heads back to Rosewood High, much to the liars' dismay.

Aria, Emily, Hanna and Spencer are sure that Mona is up to her old tricks again, but can they prove it? Meanwhile, Aria's fears about her father grow stronger.

Meredith helps take care of Aria when she is sick - but could she have ulterior motives?; Spencer surprises Toby for their anniversary.

Will their secrets drive the girls to take desperate actions that could make things worse? Plus, Emily learns more about what Ali may have been hiding the summer before her murder.

Alison's family is set to bury her again, now that they have her remains, but the girls are divided about going to yet another memorial; Emily visits Dr. Sullivan.

Spencer takes her anger and hurt over her breakup out on Mona; Aria finds she is spending more time with Wes; Emily and Jason work together.

Holding new information about Detective Wilden, Aria, Emily and Hanna are on the hunt for answers about the detective's past; Spencer finds someone to lean on.

Spencer is now ready to talk, but Emily is not ready to accept what she has to say. Hanna helps her mother and keeps a new secret, and wonders if "A" had something to do with it.