After being gone for so long, Spencer comes back home and acts like she is okay, but Hanna, Emily, and Aria don't believe her.
All four of the Liars are at a crossroads. Aria is battling her doubts about staying with Ezra while he manages his new family members. Emily is trying to prove to Spencer that her suspicions were inaccurate, but potentially at a high cost. Hanna finds herself in the midst of Caleb's family drama when it's revealed that Jamie isn't the most trustworthy. Spencer is attempting to find out the details of Mona's stint at Radley.moreless
The Liars all agree that Spencer has not been acting like herself, so when she goes MIA they don't immediately panic, until her family announces that they don't know where she is either. Hanna, Emily and Aria then attempt to track her down, and hope that it isn't A that has gotten to her. In happier news, Emily gets the opportunity to meet Olympic swimmer Missy Franklin.moreless
As Aria adjusts to Ezra spending time with Malcolm, Hanna deals with an issue regarding her mom, which may or may not be an accident caused by "A". Meanwhile, Spencer is ready to confide in Emily, but Emily has her doubts about what Spencer has to say.
The Liars become extremely suspicious of Detective Wilden, and begin hunting for answers. Unfortunately, he's hot on their heels, which may halt their investigation before they get all the answers they need. Meanwhile, at the urging of her best friends, Spencer finds someone to confide in.
When Aria gets the flu, Meredith volunteers to take care of Aria, but Hanna and Emily don't like the idea of Aria being alone with Meredith and want to figure out her motives. On Spencer and Toby's anniversary, Spencer wants to surprise Toby with a gift but it doesn't go as planned.moreless
The girls are divided about going to Ali's memorial service. Elsewhere, Emily deals with unresolved feelings about Nate's death.
Aria wants to tell Ezra about his son, but she worries that the news might damage their relationship. Elsewhere, Hanna is convinced that Caleb is keeping a secret from her, and Spencer decides she's done with game playing.
After what happened with Toby, Spencer doesn't know what to do and ends up doing something she will regret in the long run when it comes to "A". Hanna tries to bring Caleb and his father closer together but it doesn't go as planned. Aria learns that Wes and herself have something in common. To help understand what Alison could've been doing before she was killed, Emily takes a trip with Jason to help explain what happened at Jersey Shore.moreless
Suspecting Byron of killing Alison, Aria must investigate her own father, receiving help from both Ella and Meredith but begins to fall ill. Emily and Paige struggle to overcome past events. Spencer battles it out with Mona in order to become team captain of the academic decathlon. Meanwhile Hanna confronts Lucas and Mona.moreless
Mona is released from the sanitarium and returns to school, but she faces an uphill battle in which she must prove to Hanna, Aria, Emily and Spencer that she has transformed and can be trusted. Hanna wants to be Mona's friend again but feels that she can't trust her.
Hanna, Aria, Emily, and Spencer attend a Halloween party on a train, where they encounter unexpected guests as well as surprising tricks from someone disguised as "A."
Maya's trial gets underway, and Emily can't stand the media attention. "A" then extends a branch to the girls, who are skeptical; and someone close to the girls betrays them.
Spencer finds out Paige's violent past with Alison and warns Emily about her, but Emily is weary to take her advice. Meanwhile, Aria tries to help Ezra put his past behind him, but this ends up being more difficult than she anticipated.
Hanna and Emily try to figure out clues about Maya at the Kahns' cabin in the woods. Meanwhile, Spencer investigates Noel; and Aria tries to understand what she's learned about Ezra's background.
Hanna receives yet another text message from "A" concerning Caleb. Elsewhere, Aria and Spencer head to the Kahn brothers' party to confront Jenna about her truthfulness.
Emily tries to figure out what happened the night she was drugged and also tries to fix things with Paige. Ezra's mom gives insight into Ezra's past to Aria. Spencer and Caleb hack a website for Mona and Hanna also tries to help out.
Hanna thinks she is being framed. Mona is asked for assistance from Aria. An oldacquaintanceof Ali and Jason shows up in town.
The girls want to set a trap but the plans look like they might backfire.
On the night of Jenna's birthday party, Garrett gets a pass out of jail to visit his mother. Emily will get a look from the inside while working the party, Aria will be working the crowd and Spencer will be staked out at Radley Sanitarium.Hanna's recent heartbreak leads her to a shocking discovery.moreless
Caleb is mad that Hanna is spending so much time with Mona; Aria doesn't want to tell Ella about the situation of Byron and Meredith; Spencer wants to know the truth about Melissa; The girls find out the identity of the Black Swan.
Spencer's mom decides to take Garrett as a client. Spencer is convinced that her mother only agreed to do this by force. After she begins to investigate, her suspicions are not confirmed and she comes across a bigger Hastings family secret.
The girls are stressed out when a new message from A appears; When she starts remembering things from "that night", Emily's drive to succeed at school is put on hold.
A summer has passed and the girls reunite in Rosewood and try to get over whats happened.