Read spoilers at your own risk! For more on Wetpaint Entertainment's philosophy on spoilers, click here.
Here's the quick and dirty rundown of what we learned.
Before Ali died, she was in a war with Paige, who she called "Pig Skin." She told the Liars "Pig Skin" was psychotic, and at one point Paige apparently kicked her in the back during a soccer game. CeCe thinks Ali was a bit scared of Paige. Maybe that's why she went to extreme lengths to get control over her.
See, we learn in a flashback that Ali pretended to be Emily (Shay Mitchell), and tricked Paige into thinking Emily had a crush on her. She told Paige to write "Emily" a letter, which Ali then took. If you remember, Paige's dad is a homophobe, and Ali threatened to show him the letter. "I own you," she told Paige, who looked very angry. According to Paige, Ali teased her relentlessly, to the point where Paige started to self-harm over it.
Meanwhile, in the present, when Emily first asks Paige about her history with Ali, Paige says she didn't know her at all. She eventually opens up, but why the huge lie at first? Was it just because of the bad memories, or something else? And isn't it kind of weird that Paige has apparently had a thing for Emily for years?
What do you make of this history? Let us know in the comments below.
Catch the PLL Season 3 summer finale on Tuesday, August 28 at 8 p.m. ET/PT onABC Family.