The PLLs work with Mona to try and get some clarity on A.

The presence of Mrs. DiLaurentis continues to unnerve all those around her; Toby shares a heartbreaking secret with Spencer; "A" nearly kills Mona.

Hanna worries her mother is keeping a dangerous secret, which leads to an uncomfortable meeting with Detective Holbrook; Melissa returns to Rosewood.

A new detective means new questions, and the liars are asked some hard questions; Spencer lays a trap for Melissa.

Spencer and Emily visit a nearby college, but they have different agendas for their time on campus. Hanna is frantic after another horrifying discovery among her mom's things.

Trying to protect her mom gets Hanna in trouble with the cops; Searching for the recipient of Ali's mysterious phone number leads Spencer and Toby to Ravenswood.

Caleb and Toby team up to investigate "A" and what happened the night of the lodge fire; Ezra struggles with how he fits into Aria's life; Hanna tries to act normal.

Caleb tries to convince Hanna that Mona can't be trusted, causing Mona to prove her loyalty in the most unexpected way; Emily reconnects with her old boss Zoe.

Paige throws Emily a surprise birthday party; Mona's selfless act provides Hanna and her mother with their first bit of good news; Ezra gets some distressing news.

Mrs. DiLaurentis offers to let Emily move into Ali's old room; Trying to get involved in Jake's interests; Aria finds an opportunity to follow a lead.

Ezra reaches out to Aria, just as she decides to move on with Jake; A Western-themed dance turns into a two-step with "A"; Hanna is stalked by a fellow student.

An intriguing riddle from "A" has the liars hitting the road and heading to Ravenswood, where they make a shocking discovery.

The liars crash the Ravenswood Founders Day Celebration after a clue suggests Ali may be alive; Caleb meets a kindred soul, Miranda.

Now it's confirmed that Alison is alive, who was buried in Ali's coffin?

After Hanna reveals that she has Ali's diary, the liars hope it can answer some questions, but are they ready to admit which personal story is about them?

"A" goes after Hanna in an unexpected way; Spencer works overtime to decipher the stories in Ali's diary; Aria is upset with the new friend Mike has made.

Spencer's hunt for the truth takes a dangerous turn. Will Hanna be able to figure out Spencer's secret?; Emily looks to make amends with Alison through Shana.

Spencer's numerous sleepless nights, with the help of prescription pills, take a toll on her as her hunt for Ali and much needed answers continues, teleporting her into the world of 1940s film noir.

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

Emily takes up the sleuthing reins and hunts for answers about Ezra and Mona; Hanna begins a new search after being confronted by Holbrook and Tanner; Spencer and Aria lean on new men in their lives to recover.

The liars finally get answers about the night Ali disappeared. With their newfound knowledge of Ali's long-held secrets, can they figure out who "A" is?