Credit: ABC Family

One of the biggest secrets of Pretty Little Liars Season 5 is shaping up to be whatever Melissa Hastings (Torrey DeVitto) is hiding. We’re totally OK with this because it means lots of Hastings family drama aka our favorite. And, from the looks of this very serious behind-the-scenes Instagram shot from Troian Bellisario (Spencer Hastings), Melissa will be sticking around (and, most likely, keeping quiet) for a while. What is Spencer’s sister hiding?
 


She Killed the Girl in Ali’s Grave

This is the frontrunner theory right now, because the timing seems to match up. Whatever Melissa is hiding, she was hiding it before Mrs. DiLaurentis was killed in the Season 4 finale. Given that the Rosewood P.D. was abuzz with the news that Ali was alive and there was an unidentified girl buried in her grave, this theory makes a lot of sense. We also know that Melissa was not only looking for Ali the night of her disappearance, but really pissed at Ali for seeing Ian behind her back. Did Melissa go after Ali that night, only to take out the wrong girl?

She Knows Ali Has a Twin sister

We’ve long suspected that Alison has a twin sister. If this is the case, we have no idea who might know. Though we’ve always assumed that it was only the DiLaurentis family who has knowledge of the secret member of their family, now we’re not so sure. Could Melissa and the N.A.T. Club have discovered the DiLaurentis family’s deep, dark secret? This would certainly explain why they are being killed off one by one. If Ali’s sis is the killer, perhaps she would go after people to protect the secret of her existence. Perhaps the Liars aren’t the only ones who are being blackmailed to keep secrets in this town. Have the DiLaurentises’ been forcing the Hastings to stay quiet all these years? Perhaps, this is the secret Melissa and her father are so desperately trying to keep from Spencer, and why Melissa dislikes the DiLaurentises so much.

This theory would also work if a different member of the family (Jason? Mrs. D?) has a twin.
 

Mrs. Hastings Killed the Girl in Ali’s Grave

This is pretty out there. We can’t think of any motivation Spencer’s mom would have for going after the girl in Ali’s grave or to kill anyone in general. Then again, this town is full of secrets. Plus, Mrs. Hastings is looking really nervous in this sneak peek of next week’s episode. All this time, we’ve been thinking that Mr. Hastings and Melissa are protecting Melissa, but what if they’re protecting Veronica? It is exactly the kind of twist PLL likes to pull.

She Is “A”

We’re still not sure Melissa isn’t the one behind the entire “A” game. We don’t want to believe it for Spencer’s sake, but she is smart enough to pull it off, hates Ali an awful lot, and has been proven to know more about this town than most residents. She’s also known to take long, suspicious absences from Rosewood, the most recent one allegedly in London, which we have no way to prove. When Toby went to visit her there, he only found Wren another potential clue, given that Wren is known to spy on the Liars, manipulate the situation for his partner on the phone, and has access to Radley’s secrets. Is Melissa the person he reports to? Is she “A”?

What do you think Melissa is hiding? Share your theories in the comments below!

Catch this episode of Pretty Little Liars on July 1, 2014 at 8 p.m. ET on ABC.