Aria knows the truth, and we have a feeling Pretty Little Liars will never be the same.

Season 4, Episode 20 ("Free Fall") left us breathless thanks to one of the biggest revelations in the show's history, though we're still not sure if we actually like the direction the story has gone. So, what can possibly come next on Season 4, Episode 21 ("She's Come Undone")? Based on the promo, a whole lotta drama.

See, Aria is not taking this betrayal sitting down. She wants revenge, even, maybe, if it means Ezra ends up in jail. But does she crack? The promo teases that she might.

Want to know more? Here's the official synopsis:

Emily, Hanna and Spencer are concerned for Aria as they watch their friend crumble after learning shocking news about Ezra. Not knowing what is true or what to trust, Aria goes looking for answers, not wanting to believe this revelation to be true. While concerned for Aria, Spencer is not doing so well herself. Trying to prove to her parents and Toby that she can kick the habit on her own, Spencer has to be careful because one misstep could send her to rehab. But can Spencer really rein it in, or will her constant curiosity and drive be her undoing?

What do you think of this promo? Let us know in the comments below!

Catch the next episode of Pretty Little Liars on Tuesday, February 25, 2014 at 8 p.m. ET on ABC Family.

Rebecca Martin is an Associate Editor at Wetpaint Entertainment and our resident Game of Thrones, Breaking Bad, and genre TV expert. Follow her on Twitter and Google+!