The Pretty Little Liars are stepping back into time, flashing back to what happened that fateful night that forever changed their lives.

On Tuesday's Season 4 finale (8/7c, ABC Family), Spencer (Troian Bellisario), Aria (Lucy Hale), Emily (Shay Mitchell) and Hanna (Ashley Benson) will finally hear first-hand from Alison (Sasha Pieterse) what went down after she disappeared during their sleepover. More importantly, the episode will give more clues as to who Alison's deathly afraid of and whether or not the newly suspected Ms. DiLaurentis (Anne Marie Deluise) is the one who's been torturing the girls this whole time. Plus, fans will finally find out who is buried in the grave that had supposedly been for Alison. Ahead of Tuesday's revelations, the cast and producers were on hand at Sunday's Paley Festival panel, moderated by TV Guide Magazine's Damian Holbrook, to tease the finale and what's to come in Season 5. Read on for scoop:

The big flashback. We've seen bits of what happened the night Alison disappeared, but Tuesday's episode will finally fill in the missing pieces,doc martin television series, including who buried her in the grave believing she was dead, how she left things with Ian (Ryan Merriman) and how Ezra (Ian Harding) -- who we now know was with Alison that night too -- fits into the mix. Recreating the scene from the pilot, Hale said, "It was like deja vu seeing everyone in their costumes. The girls have come so far in four seasons so we had to backtrack and be like, 'Oh, none of this has happened.' It was when we were still innocent and naive about everything."

Tyler Blackburn returning to Pretty Little Liars after Ravenswood cancellation

Redemption for Ezra? Of all the characters who have disappointed and betrayed this season, it's Ezra who we found out actually had a relationship with Alison before her disappearance. So can Aria ever forgive her first love for all of his lying? "There is a shocking Ezria twist, that's all we need to say," executive producer Marlene King said when asked if Ezra would redeem himself in the finale.

An emotional Alison. We've seen Alison be bratty, manipulative, flirty and scared, but emotional? Not so much. But during the finale, Pieterse said she filmed her most challenging scene to date. "There was one day where it was ... emotionally tolling. We had a 16 or 17-hour day and all I was doing was crying." Added King, "On that day, which you'll see this in the finale, it's emotionally exhausting to watch and it was emotionally exhausting for all of [the actors]. It was brutal, but beautiful."

Season 5 hits the reset button. Regardless of Tuesday's outcome, it's clear that Alison will remain a big part of the series. Moving forward, she'll be "out" about being alive. "[Season 5] feels like a whole new show because there are five Pretty Little Liars now," King said. "It's going to affect them all individually. It's going to affect them as a group. It's going to affect their relationships with their young male and female partners. Season 5 is shaping up to be emotionally the most complex season we've had so far." Added Pieterse,Elementary Season 2 DVD Box Set, "Welcoming [Alison] back won't be as easy as it should be."

Pretty Little Liars Executive Producer: Aria will finally learn the truth about Ezra

A homecoming for the 100th episode. Following the cancellation of the show's spin-off Ravenswood, it was announced that Tyler Blackburn, who plays Caleb, will return as a series regular. His return, King said, will be in the show's milestone 100th episode which will be the fifth episode of Season 5.

A conclusion to Ravenswood. Speaking of Ravenswood, the producing team said they hope to wrap up some of the spin-off's unresolved mysteries on Pretty Little Liars. "We're going to try,Boardwalk Empire Season 3 DVD Boxset, in as satisfactory of a way as possible not to leave you guys hanging," executive producer Joseph Dougherty said. "We knew where we were going, they just told us to get off the train."

A Pretty Little Liars movie? It's definitely possible! "We talk about it all the time," King revealed. "We'd love to continue to explore this great world and these great characters. ... I'd love to write it and direct it!"

The Pretty Little Liars season finale airs on Tuesday ,find music from tv shows;at 8/7c on ABC Family.