The residents of the sleepy village of Daggorhorn have long kept the local werewolf at bay with a monthly sacrifice. But now the Wolf has told Valerie—the only villager who can hear his voice—that she must surrender herself to him or everyone she loves will die. In Red Riding Hood, a novel that 22-year-old Sarah Blakley-Cartwright has written based on a screenplay by David Leslie Johnson, the plot of the traditional fairy tale has thickened substantially. On sale January 25, this Little, Brown/Poppy book ties into the Warner Brothers film that is set for March release. Directed by Catherine Hardwicke of Twilight fame (who contributes an introduction to the novel), the movie stars Amanda Seyfried, Gary Oldman, and Julie Christie.

Blakley-Cartwright, who received a degree in creative writing last year from Barnard College, was mulling over what she’d do after graduation when she ran into Hardwicke, a family friend she has known since she was 13. She mentioned to Hardwicke that she had recently won the annual Lenore Marshall Barnard Prize for Prose—a fortuitous turn of conversation.

“The next morning, Catherine called and suggested I try to write a novel to go with Red Riding Hood, her new movie,” says the author. “I was in the middle of finals, but I said I’d love to try. So I put aside my physics textbooks and picked up the script. And reading it in my sweatpants in the Columbia library, I went from blushing over the romance scenes to biting my nails in fear. I became entirely immersed in this magical, lush, dark medieval world that David and Catherine had created. It was an amazing feeling.”

Though excited by the prospect of penning a novel based on the screenplay, Blakley-Cartwright knew she had to pass muster with the publisher, which had released Hardwicke’s Twilight: Director’s Notebook in 2009 and had signed on to publish Red Riding Hood. “I knew it wasn’t a done deal,” says the author. “I’d gotten through Catherine’s gate, but now had to get through Little, Brown’s gate, which was a scary thought.” She was terrified on the way to her initial meeting with Erin Stein, senior executive editor of Little, Brown Books for Young Readers. “But when I got to her office, it was filled with toys, and I was overcome with gratitude,” she recalls. “I said, ‘Thank you, universe, for sending me an editor who likes to play!’ ”

Stein was taken by Blakley-Cartwright’s writing samples, noting “she has a wonderful, descriptive, poetic sensibility,” and was also impressed by the sample scenes the writer turned in based on the screenplay. “Sarah really captured a YA voice,” Stein says. “She’s young, and her writing speaks directly to teens. She was a dream to edit, and it was exciting to work with her on the ground floor of her career.”

Once on board as the novel’s author, Blakley-Cartwright didn’t hole up at home with her computer. Instead, at Hardwicke’s invitation, she flew to the Vancouver set where Red Riding Hood was filming. “I went a few days after graduation, thinking I’d stay a couple of days and find my groove there,” she says. “But I didn’t come home for almost three months.”

On the set, Blakley-Cartwright saw Red Riding Hood’s drama unfold as she watched the actors perform, and had a chance to interview them about the characters they were portraying. “It was a stunning set, and seeing the actors at work really informed my characters,” she says. “Being there was an amazing gift. To have all of that right there in front of me provided a road map for my writing. Obviously this project is a team effort, and seeing all that creativity first-hand—how could anything be better for a writer?”

Rather than strictly adapting Johnson’s screenplay, Blakley-Cartwright sought to flesh out the characters in her novel. “I hope I was able to add to the story,” she reflects. “The first quarter or so of my novel is not in the movie, in fact. At the start of the film, a character dies, and Catherine thought it was important to give readers a sense of who she is. This isn’t just a fairy tale, but a coming-of-age story that is a parable about power and abuse of it. It was very important to me that I capture the political dimension of the script as well as the social dynamics it established.”

Red Riding Hood, which has a 100,000-copy first printing and has been sold to publishers in 13 territories, will be published simultaneously in trade paperback and as an enhanced e-book. Components of the latter include a video discussion among Hardwicke, Johnson, and Blakley-Cartwright; an audio of Hardwicke reading her introduction; blueprints and photos of the set; sketches of the costume designs; and storyboards from the film.

Issuing an enhanced e-book simultaneously with a YA novel breaks new ground for the publisher. “Catherine Hardwicke has an extraordinary visual sensibility and a passionate teen fan base, so this was the ideal vehicle for us to produce our first simultaneous enhanced e-book and print publication,” observes Megan Tingley, senior v-p and publisher of LBYR. “The Red Riding Hood novel and enhanced e-book offer a unique opportunity to engage fans in the book, film, and digital arenas, providing a truly enhanced entertainment experience that will resonate powerfully with teens.”

Readers will also have access to what Stein calls “an extra bonus”: a final chapter to Red Riding Hood that will be available free online (at www.redridinghoodbook.com) after the film’s release. “The story is a whodunit, with lots of wonderful red herrings, and with every chapter readers are led to think someone else is the werewolf,” she says. “The novel has a great ending as it is, but there’s an extra surprise in the online bonus chapter.”

Scheduled to coincide with the film’s March release, Little, Brown’s national advertising campaign for Red Riding Hood will include spots in Life & Style’sprint edition and on its Web site, and will target various teen outlets. There will also be extensive cross-promotion with Warner Brothers. The publisher will distribute copies of the book at national and international press events for the film and at advance screenings in 30 top markets.

Red Riding Hood by Sarah Blakley-Cartwright. Little, Brown/Poppy, $9.95 paper Jan. ISBN 978-0-316-17604-0