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?

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.

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.

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?

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.

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.

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

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

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

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

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.

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

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

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

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

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.

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.

Mona returns to Rosewood in a very fragile state as she must answer to the police for faking her death. Matters only get worse when she is confronted by Lesli’s sister about Lesli’s inadvertent involvement in Mona’s plot. Hanna is determined to help Mona out, not only to reassure her she is safe from Alison but also to try and repair Mona’s friendship with Lesli. Emily tries to help Sara with her troubled home life by encouraging her to explore the possibility of emancipation. Spencer, on the other hand, finds help from someone from her past.

Meanwhile, Alison grows closer to Lorenzo as she looks for support outside of her family.

With all signs pointing to Lesli as the tormentor in the hoodie, the PLLs are on a mission to get concrete proof before bringing their findings to the police. But as the girls ramp up their investigation, "A’s" threats escalate.

Meanwhile, a friend of Emily’s makes her a surprising offer, and Spencer is pressured by her family to make an important decision.

It is prom time at Rosewood High School, except for Alison, Aria, Emily, Hanna and Spencer who have been banned due to "security" concerns. As the girls see this as the final humiliating blow to their high school careers, the girls' mothers try to make the best of a bad situation by offering a home prom in Spencer's barn. At first reluctant, the PLLs agree and try to make the best out of a bad situation. But one to never miss a formal, Charles has other plans in store to make this a night they will never forget.

Meanwhile, Veronica, Pam, Ashley and Ella use prom night to touch base on everything that has happened to their daughters.

Aria, Emily, Hanna and Spencer find themselves back in familiar territory with the Rosewood P.D. knocking at their doors looking for answers and their actions now affecting the loved ones around them. With her mother's job on the line, Hanna tries to come up with an alibi that could save all four of them with the help of her old high school friend, Lucas.

Meanwhile, Emily comes clean about the last five years, and Aria goes the extra mile to keep Ezra's second book in play with her boss.

As romantic relationships move forward, the Liars investigate a new suspect in the murder case. With Ezra back in Rosewood, Aria must tell him the truth about her involvement with his book. Spencer and Caleb deal with a media leak that affects the campaign. Hanna takes a look at her life after an incident at work. Emily gets harassed by the stalker while she continues the search for Sara.

Meanwhile, two lovers finally tie the knot with the help of a special officiant.