So, now we know Ezra Fitz's (Ian Harding) secret: He's writing a true crime novel about Alison. Or at least that's what he claims he's been up to. We're still not entirely convinced this is the full story, but either way it's a pretty huge betrayal. So, what comes next? The promo for Pretty Little Liars Season 4, Episode 21 ("She's Come Undone") reveals some interesting clues.

It looks like Aria does not take this revelation well. At all. So what happens when Aria comes "undone"? Here's that the preview tells us.

1. Aria tells the Liars? Based on the shot of Aria sitting despondently on a couch with her friends around her at :05, we assume that she fills the other Liars in on what she's learned.

2. Sadness, sadness everywhere. Is that Aria sitting slumped on a bench at :07? Or maybe Spencer? Whoever it is, she doesn't look happy. And it's definitely Aria who is lounging around on her bed at :10, looking incredibly depressed.

3. Burning pages. At :12 we see Aria burning a piece of paper. Hmm. Maybe a memory from her time with Ezra? Our could this be linked to the mystery in some way?

4. Could Ezra go to jail? Aria does more than mope around. At :13 she declares to Hanna that she won't be the "only one who suffers from this." "Ezra's not just gonna suffer!" Hanna counters. "He's going to go to jail." Well, yeah. He kind of deserves to, if you ask us.

5. Spencer is still breaking down. At :16 we get a shot of Spencer still looking a mess. Clearly, she's not done with her pill popping yet.

6. Who goes too far? The promo warns that "they'll all pay the price when one Liar goes too far." Is that Liar Aria? This vid certainly suggests so, thanks to...

7. Aria flips out! At :19 we see Aria flipping out, screaming, throwing papers, breaking lamps... The other Liars appear to walk in on her at :22. "Oh my god!" Emily gasps.

Check it out for yourself.

Catch this episode of Pretty Little Liars on 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+!