Credit: Norman Buckley Instagram

This week, we’ve been privy to many behind-the-scenes photos from the Pretty Little Liars 100th episode set,  including this one, which, has Aria (Lucy Hale), Spencer (Troian Bellisario), and Hanna (Ashley Benson) looking grumpy. What has them in such a strop?

In the photo tweeted by director Norman Buckley, we see the three Liars in a camera screenshot. They appear to be at Rosewood High, and they all look pissed. Hanna has her arms all-out folded and Aria is glaring down the hallway. Spencer looks more focused than angry, but the girl’s definitely not smiling. Who are they staring at?

We wonder if the Liars’ glares might be directed at their bestie Alison (Sasha Pieterse). The former mean girl will be back in Rosewood in Season 5 and, though we’d like to believe that she has learned the error of her mean girl ways and all five Liars will BFFs again, we’re hesitant. With Ali so out of her element, will she freak out and start manipulating her classmates, neighbors, and friends right where she left off? Or, perhaps, she’s found new friends.

Ali isn’t the only potential target of the Liars’ frustrations. The 100th episode will bring Jenna (Tammin Sursok) back into the fold. Though the relationship between the Liars and Jenna has thawed a bit since the early seasons, there is still no love lost between them. Is Jenna causing trouble with her re-emergence onto the scene? Are she and Ali talking? And why is Jenna back?

Why do you think the Liars look so pissed? Share your theories in the comments below!

Catch the next episode of Pretty Little Liars on Tuesday, June 10, 2014 at 8 p.m. ET on ABC Family.

Kayti Burt is a contributing writer for Wetpaint Entertainment with a penchant for all things pop culture. Follow her on Twitter and Google+!