'Pretty Little Liars' Halloween Special: 'More Thrilling And Scary Than The First,' Says Marlene King

Pretty Little LiarsAll aboard the A train! The "Pretty Little Liars" Halloween special airs tomorrow night at 8/7c on ABC Family, and fans are definitely in for a dark ride as Rosewood's residents celebrate All Hallows' Eve on a locomotive.

The episode will boast plenty of thrills and chills, not the least of which will be a cameo by former "American Idol" contestant Adam Lambert, who will perform two songs in his sexy Glampire finery.

In anticipation of "This Is A Dark Ride," we hopped on the phone with executive producer-writer Marlene King, who revealed details aplenty, including a hint as to who will not make it to the end of the line alive! Check it all out after the jump!

Hollywood Crush: You declared last year's Halloween special the scariest "Pretty Little Liars" episode ever. Will this one top it?

Marlene King: Yes! In the way that I think the show continues to sort of progress to darker places every season, I think the Halloween episode is darker and definitely more filmic and more thrilling and scary than the first.

How does the episode fit into the series' continuity? Does it pick up right after the events of the mid-season finale?

It does, actually. We learned that Toby was A. We call them "the closers"—the little tag scenes from A's point of view—A was RSVPing to the Halloween train that the pretty little liars will all be on. So it's sort of picking up a few weeks later.

Why a train?

It was about this time of year [last year], and I saw an advertisement in a magazine for the Napa Valley Halloween Train, and I ripped it out and just sort of started passing it around to our group here, and [saying], "Wouldn't it be fun for next year?"

The idea of a train feels a bit Hitchcockian.

It definitely is. And we try to pay homage to a lot of Hitchcock movies in our finale episodes and specials. And this one pays a lot of homage to Hitchcock films.

Speaking of Hitchcock, what are some of your favorite scary movies?

Well, "Silence of the Lambs," I love.

I was just quoting that line, "It puts the lotion in the basket..." the other day!

Isn't that the best? "Or else she gets the hose again." It's so good! That's one I watch over and over again. I loved "The Omen," "The Exorcist" and the original "Halloween."

You have a really fun guest star for this episode in Adam Lambert. How did that cameo come about?

We sort of put the word out there that were were looking for a musical guest star for the episode, and he was a fan of the show, and they reached out to us, and we were so excited. It's just so much fun. It's great energy. He just fits into our "Pretty Little Liars" world.

The girls had a hand in picking their costumes last year. Was that the case again?

This year's theme is really more movie costumes or period costumes. We really did want to have this sort of nostalgic, '40s kind of feel, and everyone embraces that except for Shay's character, who plays Barbarella out of the '70 I guess, or the '60s. But that's the character she really wanted to play, and it fits perfectly within the show.

Rumor is, someone will die in this episode. Can you tell us anything more?

Just that someone will die. [Laughs] Someone is not getting off the train alive. I will say that it goes back to our theme song, "Only two can keep a secret if one of them is dead." The person who dies is about to reveal a very big secret to the pretty little liars, and that person is killed before the complete secret can be revealed.