If you thought the unfolding mystery that made "Pretty Little Liars" a breakout hit during the first half of its freshman season was juicy and, at times, chilling, the ABC Family series is just getting started. The drama, focusing on four teens and the mystery that began when their friend Allison disappeared and was later found murdered, is back tonight with new episodes that will surely answer some questions but also raise more in order to keep things spinning for seasons to come. As we join Aria (Lucy Hale), Hanna (Ashley Benson), Spencer (Troian Bellisario) and Emily (Shay Mitchell), the foursome is immersed even deeper in romance and family drama while the seemingly ever-present "A" continues to wreak havoc on their lives.

While the identity of "A" is still very much unknown, Executive Producers I. Marlene King (who also created the show) and Oliver Goldstick chatted with our Jim Halterman about the demographics for the show not only being teens, adapting the show from the popular book series, if they actually know who "A" is and whether viewers will find out anytime soon.

Jim Halterman: I know adults who are pretty addicted to "Pretty Little Liars" so it's clearly not just a teen show. Was that a goal in the beginning?

I. Marlene King: We really had a demographic in mind when ABC Family decided to make this show and it was teen girls and their mothers. I'm not a teen girl, I'm in my 40s and I love the Sara Shepard books. I think universally what's fun about the show is the mystery and I don't think it matters if you're a guy or a girl and what age you are. Everybody loves a really good mystery and we stay true to the trueness of who these characters are and this fun, juicy mystery. We've started expanding the audience we thought we were going to have.

Oliver Goldstick: The parents are shadow figures in the book: it was not [Sara Shepard's] intention to flush them out but once you have actors cast in roles they can't be Charlie Brown's parents. Once we had people there, we knew we would have to develop these parents and they would evolve. In the books, some of them wouldn't have first names. We are a multi-generational show and we were encouraged to do that. I believe the bottom line is we have all been teenagers and there may still be issues from those years that might not be resolved and you still think about it. The idea of loss, which most teenage shows don't deal with - dealing with a friend dying - is deep and heavy. The show doesn't deal with that on a weekly basis but we do deal with it and I think that's something else the audience will connect with.

JH: When you adapted the book, Marlene, how much leeway did you have to go off in your own direction?

MK: When I read the first book that Sara wrote, it was sent to me by ABC Family and I finished it and the very first book is what the pilot is. I called the executive at ABC Family and I said, "Send me the second book right now!" I was so into it and each book answers questions and then asks questions and I was so intrigued. It just had the right amount of soap and the right amount of mystery and I thought if we can capture that in a TV show then people are going to be as excited about it as I am. I think we got lucky with that formula. It's two shows in one - it's a soap and it's this great mystery and nobody has done that in TV for this audience. The discussions that the producers and I had with ABC Family when we were making the pilot was all about tone. We had probably 20 meetings that didn't talk about anything but tone. It wasn't until ABC Family saw the pilot that they grasped what the tone was. It's really something that is so unique to itself that you can't really discuss what it is. It's so many things in one that it became its own original voice.

JH: How easy or difficult was it to cast the show?

MK: It was a challenge because we felt like we had something special and we needed those pieces to fit together because it really is a true ensemble between these four girls. Bob Levy, who is [also an executive producer] of the show, and I cast the pilot together. The first person we cast was Lucy Hale as Aria, and she had come off of "Privileged," which Bob had also worked on. The next person we cast was Troian Bellisario and as soon as she came into the room we knew she was Spencer! She was so smart and so gutsy. Then we cast Shay and she felt so right. The hardest person to cast was the role of Hanna. Ashley Benson had been on "Eastwick" and it was cancelled on a Monday night and on Tuesday morning we had her reading for the role of Hanna. Then we were off and running. It was meant to be!

JH: With such a female-dominated cast, what's in the show for guys to connect with?

OG: For men, I honestly believe that it's the mystery of the murder and the puzzle of the show - it's "Twin Peaks"-like - and we are tapping into something that has suspects and murders. Why would this person suddenly disappear like this? What went down before she went down? I think they might not want to admit it - and I've worked on "Desperate Housewives" and "Ugly Betty" - but you know they watch every episode.

JH: What are the parameters in working for ABC Family? They go a lot further than they used to but is there a boundary that you know you can't cross?

MK: They sort of have a universal theme that they don't want really bad behavior to go unpunished. For example, Aria and Ezra (played by Ian Harding) are in a student/teacher relationship and that seems cutting edge and oftentimes it's not acceptable behavior so we have to make sure that it isn't just a typical relationship and that there are consequences to their relationship. We have to make sure that the behavior that is not always acceptable has its consequences. Other than that, they've been very generous with us with Emily's sexuality and pretty much everything we've done on the show. They're very generous in regards with what they let us get away with.

JH: What do we see in these coming episodes?

OG: Some great stuff. On the emotional and personal front, Hanna has an incredible new love interest which I think is going to be very exciting for the audience. Spencer makes a very interesting liaison with one of the current characters in the show and that's going to be surprising. Emily faces some real difficulty with other athletes on the swim team; it seems to be homophobic but we work through that. With Aria and Ezra, the students are onto them, which is going to raise their terror level to orange and that's by episode two. Also, in Aria and Ezra, the first few episodes deal with the whistle blowing of it all and whether they're going to get caught and then we settle into this interesting can you have a relationship when there's no bubble? How many places can they go and be seen together? How does a relationship develop in those constraints? We do explore them as a couple and there are some interesting things coming up. With the mystery of it all, we're going to the night when Allison disappeared and some memories that are jogged that will reveal some shocking things of where she was coming from before she came back and arrived at that party. We're going to explore the context of the night Allison disappeared and was murdered.

JH: Do you mind having the show called a younger "Desperate Housewives" as it has been in the press?

OG: You know, they have to sell shows and I think that's publicity and they have to make comparisons. There are parallels. We have four very attractive girls who are different and bonded by a death and we dealt with the same thing with the "Housewives" in the first season. That's the same thing here. The template is similar so I can see why they're drawing parallels.

JH: Is the "Who is A" question going to wrap up by the end of season one or is it a series-long thread?

OG: I think we're keeping it as a thread. It's certainly a thread throughout the books. It's one of the most delicious elements of the show. Guessing who that is seems to be a cause of pleasure in guessing who the murderer is. People just love asking me "Is it so and so?"

JH: While I don't expect you to tell me who "A" is, do you and Marlene at least know who "A" is?

OG: Yes.

"Pretty Little Liars" airs Mondays at 8:00/7:00c on ABC Family.