Aria returns to Hollis a year after the mysterious disappearance of Allison and picks up her friendships with Spencer, Hanna & Emily. The girls are stunned when Allison's body is recovered, turning the missing persons case into a murder. Even more disturbing is the message they all receive that spooks them into wondering if their presumably-deceased friend could still be alive.

The circumstances surrounding Alison's disappearance continue to haunt the girls, 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. 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.

As the girls try to pay tribute to Alison's memory, the four friends are faced with unresolved issues. Aria has an unsettling encounter with her father's former mistress, Meredith. Emily is forced to see Toby Cavanaugh in a new light. Spencer is reeling in the wake of a vengeful Melissa. And Hanna is desperate to have her boyfriend, Sean, forget the "old" Hanna. Meanwhile, Detective Wilden uses his new connection to Hanna and Ashley to his benefit. But will he get the answers he's looking for by making himself at home in the Marin household?

Tired of being harassed by "A," the girls decide to put a stop to the anonymous emails and text messages by blocking all unknown users. But even with the mysterious ghost no longer looming over their heads, the girls' problems are far from over. With a surprise visit by a father, a surprise gift from a prospective paramour, getting some unwanted advice and an undeserved scholarly accolade, the girls' lives continue to get more complicated by the day. And after dealing with all of that, did the Pretty Little Liars really think they could keep "A" away forever?

Trying to ignore "A" backfired for the girls, and now they must pay the penalty. Whether it's a family in crisis, parental praise for an undeserved honor looming over their heads or wearing totally unfashionable scrubs while working off a debt – the girls must deal with it all. And on top of that, "A's" lipstick message is still haunting them. Meanwhile the girls must also deal with typical teenage drama – the boy kind – when a new boy arrives and pushes the status quo, a secret love is tested, a new romance blooms and an old romance is floating in the grey area.

The homecoming decorating committee is knee deep in balloons, and girls are jockeying for position to be the queen, while four friends from Rosewood just try to stay afloat. Dealing with heartbreak, a boyfriend's virginity pledge and a vengeful sister all take a backseat when one girl makes a shocking homecoming date choice that puts her in a possibly sticky situation. Will the girls be able to protect one of their own, or will the evening turn out to be a night they can never forget?

In the aftermath of the disastrous homecoming dance, the girls try to sort out the devastation that is left behind. Parents, boyfriends (secret ones, possible ones and current ones), siblings and friends are all in flux, and if the little liars don't act fast, the situation could go from bad to worse. And to top it off, the girls are sitting on some killer information about Toby that some people would die to get their hands on. Meanwhile, "A" isn't the only one sending Aria text messages as tensions rise in the Montgomery household.

After much planning, the day of Alison’s memorial is around the corner and the girls are ready to say their goodbyes. But when Alison’s brother Jason arrives, Spencer, Aria, Hanna and Emily quickly learn that saying goodbye is at the bottom of his list. As Jason takes over, and Detective Wilden returns, will the girls be able to celebrate Alison’s life in the peaceful and positive way they were hoping for? Meanwhile, Hanna is forced to deal with a situation at home that could really cramp her “it girl” status.

A day of SAT testing is put on hold when a violent storm hits Rosewood. But instead of enjoying the academic postponement, the girls are stuck in the school dealing with the drama that follows them everywhere. Each girl finds herself in the middle of a tense situation — whether it's between friends, potential love interests, a boyfriend and a parent, or between the past and the present, the girls will come out of the day thinking the SATs would have been a piece of cake compared to what they went through. Meanwhile, Byron leans on Ashley for advice on parenting as his relationship with Ella takes a turn for the worse.

When the discovery of a new piece of evidence about Alison's disappearance brings the FBI to town, the last thing the girls want to do is go "glamping" (glam camping) for Mona's birthday party. But when they get a text that insinuates that "A" will be at the party, Spencer gets the idea that it will be their chance to finally put an end to the threats. Once at Camp Mona, not even the mani/pedi station can lift the girls' spirits when the evening takes a dangerous turn. Meanwhile, the Marin financial situation is pushing Ashley to the brink.

Moments after Hanna is hit by a car, the girls’ world is turned upside down. “A” is no longer content to playing a game of cat and mouse — it has taken a far more precarious turn and now more than ever the four Pretty Little Liars have to turn to each other for support. With Hanna in the hospital and armed with the information of who “A” is, the girls are backtracking to figure out how they got to this point. How could this person know everything and want to use it against them? Meanwhile, each girl has to also deal with a secret that is either found out, confessed or confronted — proving that secrets are still abound in Rosewood, PA.

Hanna's return home from the hospital should be a joyous event, but being stuck in a wheelchair and feeling haunted by "A" makes her return feel more like a Hitchcock nightmare than a proper homecoming. Even though the girls try to put on their best effort to support Hanna, they all have troubles they have to face as well: Spencer is still reeling from Melissa's surprise, when an unexpected roadblock is thrown up in her relationship with Alex; Emily, on the other hand, is hoping that an introduction to Maya during a tense family meal will smooth all apprehensions her parents may have. Meanwhile, blackmail is in the air when Aria and Fitz suspect a student is on to them.

Relationships are in flux in Rosewood, PA, as the Liars face many obstacles. As Noel steps up his pursuit of Ezra and what he can gain from his knowledge, Aria and Ezra start to feel like there may be no way out. Emily must also deal with opposition to her love life, as her mother Pam's perceived tolerance of Maya comes to a screeching halt. And Spencer must now handle the return of happy newlyweds Melissa and Ian, even though her suspicions of Ian's ties to Alison grow. But with the other girls' support and unexpected help form an unlikely source, the future for the Liars doesn't look so hopeless. Meanwhile, "A" has Hanna jumping through old habit hoops with regard to the stolen money. Will Hanna fall back into her old ways, or does she have the will power to stand up to "A" and her games?

As the school gets ready for the dance-a-thon, Aria, Emily, Hanna and Spencer have more on their minds than raising money for the school trip to Washington, D.C. Hanna is having a hard time finding a job to help her family's financial situation, but when "A" has a job for her, will Hanna be able to refuse? Emily can only think of Maya and is desperate to speak to her — so much so that she enlists the help of Caleb, the new bad boy in the school. And as an important piece of property goes missing, Spencer finds being in close quarters with her new brother-in-law, Ian, more difficult than ever. Meanwhile, Aria's former babysitter, Simone, comes back to town for a surprise visit. But what should be a happy reunion quickly becomes a nightmare for Aria when Simone sets her sights on Ezra.

The girls try to resume a sense of normalcy in their lives, but even the simple tasks of dating and extra-circular activities meet with strife. Emily must deal with a jealous teammate who is threatened by Emily’s return to the pool, as Aria and Ezra plan their first date out in the open. And Hanna is still stuck playing “A’s” game, but the next hurdle might just have complications for another Liar. With “A” pulling the strings and making matters worse, will the girls be able to weather the storm and lie their way out of it, or will they have to face the ugly truths? Meanwhile, Spencer turns to Ali’s brother, Jason, for information about the night they believe Alison died, only to have to face part of her unpleasant past with Ali.

A crucial swim meet for the Rosewood Sharks is the setting for Aria, Emily, Hanna and Spencer to experience a lot of turmoil. Emily and Paige go for round two, as they are pitted against each other to compete for the anchor leg of the big race. And Caleb calls in his favor with a guilty Hanna as she tries to deter Aria from asking too many questions about Ella’s ticket to the museum opening. As secrets start to be revealed and antagonists become less threatening, will this become a game changer for the girls? Meanwhile, Spencer takes on the task of tutoring a fellow student to try and get some answers.

What happens to one liar when parent-teacher conferences come around and her father sits face to face with the love of her life? What about when another one reaches out to a tarnished innocent, when no one else will? And what about the liar who is taken by surprise by an unpleasant person? And don't forget about the last liar who is getting way too comfortable with someone she might not want to trust. Whatever it is, "A" is sure to have something to say about it. It's now just another normal day in Rosewood, PA for Aria, Emily, Hanna and Spencer.

As their doubts, fears and suspicions grow, Aria, Emily, Hanna and Spencer start to wonder what the true face of evil looks like. Is it the girl who holds a grudge and will do anything to keep her loved ones near? Is it the new brother-in-law who might have a darker side beneath the surface? Or is it an unknown stranger who is playing puppet master with four girls' lives? Only time will tell who the Bad Seed is. Meanwhile, Aria sees the school play as an opportunity to get closer to Ezra. But will her plan backfire and put her relationship in jeopardy?

After a shocking revelation from the police, the spotlight is turned on four little liars who look to be crying wolf. But with everything pointing to Ian, how could the girls be wrong? Or could this be just another game "A" is playing with them? With the cops now demanding answers from Aria, Emily, Hanna and Spencer, will the girls come clean about "A," or are some secrets better left unspoken? Meanwhile, secret relationships take a toll on some of the Liars while others blossom. Love is not for the faint of heart.

As the heat is turned up on the suspicions surrounding Spencer, the girls must come to the reality that they aren't the only ones hiding secrets in Rosewood. Spencer remembers something that happened the night of the murder.

Everyone has something to hide — whether it be a secret romance, who they really are, or what their true intentions are. For Aria, Emily, Hanna and Spencer, keeping things hidden is second nature, but having to live with those secrets can become a big burden. How long can Aria be with someone when they can't go out in public? Is it a true friendship when Spencer and Toby aren't able to be seen together? How truthful can Emily be when she can't be honest about whom she wants to be with? And how can Hanna move on when she secretly still wants to be with the one who broke her heart? With someone like "A" out there to watch their every move, four Liars may not have to worry about keeping things hidden for too much longer. Meanwhile, Rosewood police officer Garrett Reynolds is keeping his promise to keep a close eye on the girls — much closer than they realize.

Now that Aria, Emily, Hanna and Spencer are in possession of the information that Alison left them, the girls decide that it's time to finally put an end to "A" and the mystery surrounding their friend. But without certain proof that their hunch is right, how can the girls catch "A" in his/her own game? And with little more than a video and hazy memories of the night that Alison disappeared, the Liars may have to turn to an unlikely source of information to help them put a stop to "A" once and for all — or so they think.