A year after their friend disappears, four girls receive mysterious messages from 'A'.

The circumstances surrounding Alison's disappearance continue to haunt Aria, Emily, Spencer and Hanna as questions arise about the night she went missing.

As they try to pay tribute to Alison's memory, the four friends are faced with unresolved issues. With 'A' taunting them every step of the way, can the girls forge ahead and leave the past behind?

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 the friends' problems are far from over.

Trying to ignore 'A' backfired for the girls, and now they must pay the penalty. They must also deal with typical teenage drama - the boy kind.

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.

In the aftermath of the disastrous homecoming dance, the girls try to sort out the devastation that is left behind. If the little liars don't act fast, the situation could go from bad to worse.

After much planning, the day of Alison's memorial is around the corner, and the girls are ready to say their goodbyes. But their last-minute preparations soon get derailed.

A day of SAT testing is put on hold when a violent storm hits Rosewood, but the girls are stuck inside the school dealing with the drama that follows them everywhere.

The discovery of a new piece of evidence about Alison's disappearance brings the FBI to town, and the last thing the girls want to do is go 'glamping' for a birthday party.

Moments after Hanna is hit by a car, the girls' world is turned upside down. 'A' is no longer content to play a game of cat and mouse, and things take a far more precarious turn.

Hanna's return home from the hospital should be a joyous event, but being stuck in a wheelchair and feeling haunted by 'A' makes it feel more like a Hitchcock nightmare than a proper homecoming.

Relationships are in flux in Rosewood as the girls face many obstacles. As Noel steps up his pursuit of Ezra, Aria and Ezra begin to feel like there may be no way out.

As the school gets ready for the dance-a-thon, Aria, Emily, Hanna and Spencer have more on their minds than just raising money for the school trip to Washington DC.

The girls try to resume a sense of normality in their lives, but even the simple tasks of dating and extracurricular activities meet with strife.

A crucial swim meet for the Rosewood Sharks is the setting where Aria, Emily, Hanna and Spencer experience a lot of turmoil. Emily and Paige go for round two as they are pitted against each other.

What happens to one little liar when parent-teacher conferences come around and her father sits face-to-face with the love of her life?

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 will do anything to keep her loved ones near?

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?

Everyone has a secret in Rosewood and it's only a matter of time before it is revealed. Four girls know this to be especially true and are reminded of it on a daily basis.

Rosewood's Founders Festival sets the stage for more secrets. Everyone has something to hide - whether it is a secret romance, or revealing a true identity and true intentions.

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 the mystery surrounding their friend.

Disbelieved by police and families, the tormented quartet is sent for therapy. The chance to share at least some of their secrets proves appealing.

Emily gets a lifeline, Aria faces Mr Fitz’s farewell, Hanna confronts her father, and Spencer is troubled by Toby’s treatment, Melissa’s lies, plus Alison’s brother.

While having to stay apart, Hanna turns match-maker, Spencer exploits her sister’s loss, Emily forges a letter, and Aria is upset in pottery.

Hanna helping Lucas requires Caleb’s aid, while tailing Melissa has an unexpected outcome.

A shocking discovery finally lays to rest the killer’s identity – until Emily unravels clues that reveal otherwise.

Distracted from the charity fashion show by parental and personal factors, the teen quartet is unprepared for the final display.

Reaction to a dug-up item raises Spencer’s suspicions, an awkward dinner is disturbed at Aria’s, while Emily finds rooming with Hanna a pain.

Emily’s swimming prospects could be sunk, along with Hanna’s hopes for the future, while Spencer and Aria make a gruesome discovery.

Spencer is suspicious of what Jason is hiding in his outhouse, while Caleb learns who is after him.

Aria is warned to be wary of Jason, while over-eager Mona encourages Hanna to try bonding with Kate at a country club.

The harassed foursome face the fact they need outside help, though some problems stay strictly in the family.

In custody after a testing day, three of the girls count the cost of the tasks ‘A’ set them to save a life.

The Halloween before Alison vanished shows her controlling nature, and reveals other manipulative souls were also active.

The fractured foursome endure their legal punishment plus the pain of shunning loved ones. But changes are coming.

Hanna unwillingly allows Caleb’s involvement, while a crisis helpline call alerts Emily to a new suspect, and a birthday surprise goes badly.

Hanna fears a vengeful visitor, Aria arranges to encounter Ezra, Spencer turns investigator, and Emily worries a renewed relationship is under threat.

To protect them, Caleb and Toby are misled by Hanna and Spencer, while Aria goes out with Holden, hoping to see Ezra.

Caleb’s tech skills are used against Hanna’s wishes.

Supervised school workshops to foster honesty result in far more disclosures and discoveries outside the classrooms than within.

Caleb’s laptop leads to trouble, Aria learns what Holden has held back, and a man who had information for Alison demands money.

Mona is messaged by ‘A’ again, Ezra is tempted to leave, and Spencer wants answers from Melissa, but gets distracted.

Daughter and dad bonding is awkward, while Ashley hopes to help Hanna by involving Detective Wilden.

Jenna’s return brings conflict, Aria agrees to a risky meeting, while a bag of Alison’s possessions seems like old news.

A creepy ‘hospital’ visited by Alison holds a sinister surprise, while Caleb goes along with a sting unwillingly.

An uncomfortable close encounter with their nemesis awaits at least one of the tormented quartet, and a death is promised.

Aria watches over Ezra at the hospital, while Alison and the others set a trap for "A."

Emily, Spencer and Hanna try to adjust to the new normal; Kenneth searches for Jessica.

Alison struggles with the death of her mother, as the Liars try to navigate through her new lie.

Alison attempts to regain her position as leader of the gang upon her return to Rosewood High.

Alison returns to Rosewood High and attempts to repair the damage she inflicted years earlier.

The girls look out for Alison's safety after she is spooked by a recent Rosewood "accident.''

Aria searches for information on a patient; Spencer borrows Ezra's spy equipment.

Hanna is pushed down a dark path after Alison moves in; Aria fails in her duties as maid of honor.

Hanna's drinking gets out of control; Emily looks for information linking Alison to Noel.

The Liars try to prevent Alison from sending an innocent man to jail; Hanna seeks a normal life.

Melissa reveals her knowledge of Alison's disappearance to Spencer; Emily seeks Ezra's help.

Aria, Emily, Hanna and Spencer feel trapped and search desperately for a way out of a bad situation.

A Halloween-themed ode to viewers features interviews with cast and crew, fan questions and visits from dearly departed characters.

The girls are not feeling merry at Christmas because Spencer's murder charge looms over them. Things improve though after they see an opportunity to gather evidence to clear her name.

The Liars try to prove that Alison was involved in Mona's death; Aria worries about her future.

Spencer and Toby are at odds while Emily and Aria struggle with situations that are out of their control.

Secrets abound for Aria, Hanna and Spencer while Emily tries to let go of Paige.

Hanna refuses to let "A" frame her for Mona's murder; Spencer's actions put Toby in a bind.

Mona's friend comes to town to pay her respects.

Aria hopes Andrew can be her tutor; Spencer helps Jonny with a new project.

Hanna enters a beauty contest and turns to Emily for help; Aria asks Andrew to keep an eye on Mike.

The girls scramble for evidence as Alison considers a deal. Spencer has a night out on the town in London.

Ali considers a plea deal, but it incriminates someone else, so the girls try to help her and Mike, as well as themselves. Elsewhere, Spencer unwinds while on a night out in London

Testimony at Alison's trial reveals a plethora of lies; Spencer, Aria, Emily, and Caleb follow a string of clues in hope of uncovering information that will clear Hanna.

The prosecution calls a surprise witness in Alison's trial; the girls hunt for last-minute evidence.

Shocking secrets come to light for Aria, Emily, Hanna and Spencer as the biggest clue to the "A" mystery is revealed.