It looks like Pretty Little Liars' 'A' may not be the singular villain viewers though he/she was.

'Pretty Little Lairs' Season 5: Will Aria & Andrew Become A Couple? Brandon Jones Teases 'Growing' Relationship After Ezra

The ABC Family series is gearing up for the "MOST IMPORTANT EPISODE of PLL ever," and 'A' has more than just a little surprise up their? sleeves in "Welcome to the Dollhouse."

"'A' has always had fun playing with Aria, Emily, Hanna and Spencer, but now 'they' have the biggest game to date in store for the girls," ABC Family teased. "As shocking secrets come to light and the biggest clue to the 'A' mystery is revealed, is this one plAydate the Liars can survive?"

'Pretty Little Lairs' Season 5: Is An Eighth Year Possible? Marlene King Hints At Post-A Storyline

I can just hear the growl of frustration from PLL fans around the world as they scrap their long held 'A' theories and start analyzing the series all over again. Don't get too worked up, however. Just as 'A' enjoys teasing the Liars, the writers like to keep viewers on their toes as well. Perhaps the murderous scourge of Rosewood will only make it look like he/she is not acting alone.

Do you think 'A' is really a duo (or trio)? Sound of in the poll below!

Find out more when Pretty Little Liars airs Tuesdays at 8 p.m. ET on ABC Family. Click the video below to see a preview for the series' next episode, "The Melody Lingers On."