They may be pretty, but Aria, Hanna, Spencer and Emily are wrapped in a very ugly web of lies, deceit and murder.

The twisted tale of "Pretty Little Liars" is the most talked about show on Twitter, as the season-four winter debut generated 30,000 tweets per minute and 1.3 million in total, making it the most tweeted season premiere in TV history.

Viewers chime in as these four heroines search for clues to their friend Alison's mysterious death and their hunt for "A," the alleged culprit who has been tormenting them for years.

But did Alison fake her death? And who is she hiding from?

"We leak a lot of secrets and answers," Sasha Pieterse, who plays Alison on the show, said today on "Good Morning America" of their highly anticipated finale. "So I think we're all satisfied, but I think the fans are especially going to be extremely happy."

The avid "Pretty Little Liars" fans will be the judge of that as they tune in tonight in hopeful expectation of finding out who "A" really is, sure to tweet their every question and thought as the plot thickens further.

"There's a lot of questions that are going to be answered," Lucy Hale, who plays Aria, said, adding, however, "in the nature of our show, that only raises more new questions."

Even the stars themselves are left in the dark about the new dramatic plot twists of the ABC Family show that will ensue as they begin filming season five in less than a week, but as for tonight's finale, it's safe to say their social media-savvy viewers will be left on the edge of their seats.

"Every season finale someone either dies or goes missing," Ashley Benson, who plays Hanna, explained. "At the table read I'm like, 'Oh my God!' When you actually gasp, that's like a big moment.

"The season finales are always great. They always have good cliffhangers. And this episode we find out a lot about what happens to Ali."

The season finale of "Pretty Little Liars" airs tonight at 8 p.m. ET on ABC Family. And "GMA" viewers were given part one of the code word needed in order to unlock exclusive spoilers about the summer season.

Part one of the code is "Marlene." Part two of the code will appear onscreen near the end of tonight's episode. Once you put the codes together, head over to pllsneakpeek.com to unlock the spoilers.