With the same combination of dark mystery and wry humor as "PLL," "The Lying Game" is told from the perspective of Sutton Mercer, a popular rich girl from Arizona who just happens to be dead and somehow finds herself a hovering, unseen presence over the twin sister she never knew she had.

"I wanted to do another mystery... I wanted to do something edgy, in the same way 'Pretty Little Liars' was," Sara told us on the phone from her home in Philadelphia.

Sutton was adopted as a baby, but Emma Paxton lived with their mother until she was 5, when she was abandoned at a friend's house and eventually wound up in the foster care system. Through a convoluted series of events, Emma discovers the existence of her twin, abandons her dismal life in Las Vegas and heads off to Tucson to meet her. Only, when she shows up at the appointed meeting place, Emma finds herself in a big ol' mess of mistaken identity and thrown head-first into her sister's life.

"I know that [pretending to be your twin] certainly has been investigated in 'The Parent Trap,' and other stories, but I love twins," Sara said. "It seemed like a fun thing to look into. It's been a lot of fun. I love having both narrators as well."

While the friends in "PLL" are certainly doing their best to stop A from torturing them, Emma's got a little more at stake if she doesn't find her sister's murderer: She gets an anonymous note informing her that Sutton is dead and she'll be next if she doesn't continue the charade. Sutton, who has no memory of how she was killed, looks on as her long-lost sister struggles to become the privileged, mischievous clique leader who is both adored and feared by her peers, and who made so many enemies with her prank-playing that finding her murderer proves to be a difficult task. Luckily, Emma does have one person helping her out: cute loner-boy Ethan, the only person she's confided to about the murder.

Like with "PLL," Sara wasn't on her own in developing this story. She did it with the help of Alloy Entertainment, which conceives YA series, hires writers and sells them to both publishers and TV networks or movie studios. Sara's been working with the company, which is also responsible for "Gossip Girl," for 10 years, and she loves the process.

"It's sort of like, everybody in the room, throwing out ideas of how to make the book work, and then I outline it and make everything make sense and then write it," she explained. "I definitely have different ideas from what we throw out. The thing that I really like about working with them is that it's the collective mind that most of the time makes the books better. There certainly are times when there are just too many of us weighing in, and then it's like, 'Wait a minute, we need to step back!' But that's pretty rare, to be honest. It's really a lot of smart people caring a lot about these books and the characters and the story."

And if a street-smart character like Emma seems a little different from the suburb-perfect Little Liars, there's a reason for that. Back when "PLL" was written, everyone wanted to live vicariously through the rich and glam "Gossip Girl" types. "But with 'The Lying Game,' that was developed in 2008-2009, and you know, the stock market crashed and it was very, very different," Sara told us. "Things really changed. It was kind of like, super-glamorous maybe isn't the right place to start."

Though Sara tries to keep up with the times, she's not about to jump on the dystopian or vampire bandwagons with her books. "I think I'll stick with psychological thrillers," she said, before admitting that Sutton's ghostly presence dips just a tiny bit into trendy paranormal territory. "I thought about making the twins connect in some sort of way. We'll see. I feel like readers would love that. There was one earlier draft where Sutton was really present and she broke through and told Emma not to do something, and we scaled that back. But there might be a moment in a later book."

Come back next week for Sara Shepard's take on the "Pretty Little Liars" TV show, who A is and how her next series will play out on the screen.

Will you be picking up "The Lying Game" this weekend? Are you excited for the ABC Family series? Tell us in the comments and on Twitter!