It's finally here 'Pretty Little Liars' fans! Tonight (March 18) the Season 4 finale 'A is for Answers' airs and we will finally learn what happened to Ali the night she disappeared.

To hold the anticipation at bay a little bit longer, read on to find out what you can expect from tonight's episode (complete with obvious spoilers).

"Fans of the show have had suspicions and their own theories, so I think some of those theories will be fulfilled. But you have a lot of questions that will be answered with this episode, because you have the source right there," Lucy Hale said of tonight's episode to the Hollywood Reporter. "Now that Ali is back, we can hopefully figure out who 'A' is."

But can the girls trust what Ali tells them? Explained executive producer Oliver Goldstick, "Always take everything Alison says with a grain of salt -- possibly a mountain of salt. But there's a lot of truth that's being told, and it's pretty startling. The tension will mount right into season five."

Not to mention some interesting moments between Aria and Ali now that Aria knows Alison and Ezra were in a relationship. According to Ali herself, Sasha Pieterse, "It's awkward and it's weird, and now that they know Alison's alive, it's this weird love triangle in a way."

Also in the finale, the stakes to figure out the identity of 'A' are higher than ever. According to executive producer Marlene King in an interview with Entertainment Weekly, Ali tells the girls, "If we can’t figure out who ‘A’ is by the end of the night, I’m leaving for good."

She also joked about the reappearance of Noel Kahn, revealing, "We love to call him Whac-A-Noel because he pops up in all these crazy mysterious places. I will tease that Whac-A-Noel, as we lovingly call him, may be more involved in the story than anyone ever expected."

Talk then turned to the Woman in Black, who King explains is actually called the Black Widow.

"The Black Widow is definitely involved with our endgame Uber 'A' plan, it narrows down your possibilities of who this could be," King went on to say. "But you will see the Black Widow again, and the Black Widow is very involved, and you have seen the Black Widow this season without the costume on."

The episode will also serve as a lead in to Season 5. As King explained, "The finale leads us to a premiere that is really an extension of the finale -- it's almost like a two-part action movie."

As King teases, by the end of the episode, "Someone will be injured, yes — but breathing." Which would certainly explain why a beloved character is taken to the hospital in the Season 5 premiere.

You can catch the "dynamite" finale on ABC Family tonight at 8PM ET. We can hardly contain ourselves!