Approaching the second anniversary of Alison's disappearance, a shocking event rocks Rosewood.

One of Aria's past indiscretions is fodder for a new "A." and Emily recalls a crucial event from the night she lost her memory.

Spencer asks questions, but stumbles upon a larger secret, while Aria agrees to be Jenna's accompanist.

Visiting Mona is driving a wedge between Hanna and Caleb and Hanna is forced to weigh up how honest to be with him.

Jenna throws a party to die for and the Liars are suspicious when Garrett is let out of prison to visit his mother.

A new clue could lead the girls down the wrong path. Emily remembers something new from the other night but the recollection suggests a very surprising suspect.

Hanna is worried that Detective Bryce is trying to frame her and the others turn to a very unlikely person for help.

Spencer asks Caleb for help. Aria learns about Ezra's past. Emily is worried about how Paige will be affected by everything "A" has done to her.

After Spencer turns in desperation to Cece for help with her college application, she and Aria may find some answers at the Kahn brothers' party.

A cabin may hold the key to Maya's secrets so Hanna and Emily do some snooping.

Paige's past comes back to haunt Emily. Aria gets a surprise from Ezra's past.

As the town becomes a media circus in the run-up to the new trial, the girls are betrayed by someone close to them.

Unexpected Halloween party guests pop up at every turn and The Rosewood Halloween Ghost Train becomes one killer party.

To the girls' dismay, Mona is headed back to Rosewood High. Aria, Emily, Hanna and Spencer take very different views of the "new" Mona.

A battle of the brains stresses Spencer, Aria learns of reasons to suspect her father of foul play, Hanna confronts Lucas, and Emily gets a fright in the woods.

Ailing Aria has reason to be afraid, while Spencer’s romantic gesture results in an unpleasant surprise.

Distracted Spencer’s anger is let-loose on Ezra, hurting Aria. Emily and Hanna each end up at the police station.

Emily’s memories get muddled in therapy, Caleb’s boyhood things intrigue Hanna, Ezra’s brother brings trouble, and Spencer gets bitter.

Spencer’s misbehaviour causes concern, Hanna engineers an encounter Caleb is resisting, Emily’s detective work turns dangerous.

Det. Wilden seeks to silence those who know his secret, the heat is on for Spencer after reengaging with Wren, and Ezra’s mother tries a new angle of attack.

Death stalks someone close to Spencer, while Hanna has evidence to ditch, and Aria finds baby-sitting awkward.

Spencer’s mental state deteriorates while her friends fret. A reappearance proves miraculous and ominous.

Some secrets of Mona’s asylum stay come to light, a corpse must be faced, and a lost child tracked down.

A turncoat’s betrayal is nothing compared to the deadly trap the liars are lured into hoping to see the face of their nemesis.

The girls are reunited when they each begin receiving threatening messages from someone named "A," suggesting Alison is actually alive - and watching them.

The presence of Mrs DiLaurentis continues to unnerve those around her, especially when she gives Hanna a parrot, whose gift for mimicry provides an insight into Alison's last days.

Hanna worries that her mother is keeping a dangerous secret and is determined to protect her at all costs, which leads to an uncomfortable meeting with Detective Holbrook.

Holbrook's partner, Lt Tanner, comes to town, intensifying their investigation into the Liars and their possible connection to Wilden's death.

Spencer and Emily make plans to visit a nearby college, but they have very different agendas for their time spent on campus.

Hanna's attempt to protect her mother gets her into hot water. Hanna has some explaining to do to her parents and the police after she's found with something she shouldn't have.

Caleb and Toby team up to investigate "A" and what really happened the night of the lodge fire and encounter a source that points to a new possible identity for "Red Coat".

Hanna comes up with a plan to save her mother from a conviction and turns to the only person she thinks can help: Mona. Caleb tries to convince Hanna that Mona can't be trusted.

Paige throws Emily a surprise birthday party with even more surprising guests - Jenna and Shana. But it's the actions of "A" at the party that lead to the biggest shock of all.

Still living at a motel, Emily is taken aback when Ali's mother offers to let her move into Ali's old room and is shocked when the other Liars insist Emily take up the offer.

After uncovering evidence that suggests "A" is hiding out closer than realised, the Liars step up their investigation into their most recent suspect. Hanna continues to crumble.

An intriguing riddle from "A" has the Liars hitting the road and heading to Ravenswood, where they are surrounded by some familiar faces.

Aria, Emily, Hanna and Spencer crash the Ravenswood Founders Day Celebration after a clue in "A"'s new lair suggests that Ali may indeed be alive.

Armed with the knowledge that Alison is alive, Aria, Emily, Hanna and Spencer now have more questions than ever before.

Now that Hanna has shared with Aria, Emily and Spencer that she has Ali's diary, the girls hope it can shed light on their many questions.

Shana tells Emily that she has a message from Ali, but can Emily and the girls trust Shana? Shana ups the stakes and says that Ali wants to meet Emily, but only Emily.

Hanna's interest in crime novels helps her to come up with a plan to figure out whose body is in Ali's grave. Spencer is working overtime to decipher the stories in Ali's diary.

With Spencer's possible revelation about Board Shorts, she is now more determined than ever to prove her theory before bringing it to the other girls' attention.

This special black-and-white episode gives a nod to 1940s-era film noir as Spencer's numerous sleepless nights with the help of prescription pills start to take a toll on her.

Spencer is determined to finally tell Aria what she has found out about Ezra, but Emily and Hanna are worried about what it could do to their friend.

The Liars are concerned for Aria as they watch her crumble after learning shocking news about Ezra. Not knowing what is true or who to trust, Aria goes looking for answers.

Emily takes up the sleuthing reins as she searches for answers about Ezra and Mona. After confronting both, Emily tries to make sense of the heartbreaking situation.

Spencer is reeling about the memories from her 'lost summer', Aria is nursing a broken heart, Emily struggles with Paige's betrayal and Hanna attempts to get back into dating.

After years of questions and mystery surrounding the night Alison DiLaurentis disappeared, The Liars finally learn what really happened to her that September night.

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.

Ali’s turn at the game forces her to face a monumental personal decision, made even more difficult when A.D. triggers Ali to remember a forgotten trauma. Spencer has a long overdue conversation with her father about his past sins and recent whereabouts. Emily continues to navigate working at Rosewood High with both Ali and Paige, especially when Ali comes to a troubling realization about her pregnancy, and Paige makes a big decision. Aria continues to question the fate of her relationship with Ezra and bristles under A.D.’s taunts. And, in the search for Mary Drake, Hanna and Spencer run into a familiar face with a shocking secret.