The Pretty Little Liars Season 2 summer finale is already next week.  Can’t wait until January for more episodes? Well, you won’t have to, because on October 19,  ABC Family is airing a special Halloween episode, and you won’t believe what goes down. The little liars themselves dished a ton of details about this exciting episode during a recent set visit.

"The Halloween episode is very cool because it’s all a flashback, it’s a prequel and it’s from Alison’s perspective," says Lucy Hale (Aria). "It’s pre-A, it’s pre-death, so life is good, [the girls] are carefree and you actually get to see the girls laughing and smiling. So it’s very fun."

But despite a Halloween party that promises to be epic by way of the cast’s costumes, the episode isn’t only fun and games. "It answers a lot of questions about why Alison was the way she was,” says Lucy. "And we go back and answer questions about secrets, like my dad and his affair."

You’ll also see characters who haven’t been around for a while, or whose existence is now altered. "You get to see characters like Ian, Melissa, and Jenna when she could see," teases Ashley Benson (Hanna). "There are so many things that go on. There are a lot of clues as to who 'A' is and what happened to Ali that night. The episode is really scary and it can give you a lot of information."

Speaking of altered states, hefty Hanna is back. "Oh, yeah. I wore a fat suit," Ashley laughs. "Being in a fat suit is awesome, but not when it is mid-summer and I am outside and I have to wear it for a week straight for all hours of the day. I had to wear it for seven days. I was sweating the whole time. It was so gross, but I love playing that character. She is my favorite to play."

Though we’ve seen flashbacks on the show before, they have all been from when the girls were a solidified group, but the Halloween episode takes place prior to that time period. "You get to see who [the liars] were when Alison first picked them to be her group," says Troian Bellisario (Spencer). "So you get to see the initial dynamics of them being like, ‘I don’t know who I am yet.’ That is really cool."