The popularity of the “Twilight” saga set off a trend in teen fiction. By 2011, the only books 15-year-old Beth Reekles heard her peers discussing involved vampires, werewolves and other mystical beasts.

She’d had enough.

“I wanted to read regular high school romance, without the paranormal stuff,” says the Welsh writer, now 23. Nothing Reekles could find spoke to her, so she wrote her own book called “The Kissing Booth” and uploaded chapters to Wattpad, an online platform for amateur writers to share their work. It soon became one of the most popular titles on the website, amassing more than 19 million reads.

“The Kissing Booth” leaped from Wattpad to Random House Children’s U.K. to the Netflix Originals library over the next seven years — a miraculous feat for any self-published novel, much less a teenager’s passion project. It’s also a surprisingly successful get for the streaming platform. Just last month, Netflix’s programming chief, Ted Sarandos, called the May release “one of the most-watched movies in the country, and maybe in the world.”

So how exactly did “The Kissing Booth” reach this point? Those involved in the story’s remarkable journey to Netflix have an idea: Reekles filled a need with a relatable drama about a girl’s “first romance, first falling in love, first sexual experience,” as Andrew Cole-Bulgin, co-founder of production company Komixx Entertainment, puts it.

The plot is nothing new: spunky high school junior Elle (Joey King) begins a forbidden romance with long-term crush Noah (Jacob Elordi) after kissing him at the school carnival, risking her best friendship with his younger brother, Lee (Joel Courtney), who exists in Noah’s shadow. Critics argued that the execution of this simple plot proved quite problematic: “The seemingly fluffy rom-com is rife with sexist rhetoric, casual slut-shaming, and a ‘bad boy’ lead who never met a put-down (or a punch) he didn’t like,” reads a review on IndieWire. The movie currently has a 13 percent rating on Rotten Tomatoes.

Regardless, young people flocked to the movie, and they continue to flood the cast’s Instagram posts with praise and desperate pleas for a sequel. The three actors now boast follower counts in the millions. A quick search on Twitter produces tons of worrying tweets about how people cannot stop watching the teen flick.

“There’s a really intense level of engagement from a big part of this audience,” says Ian Bricke, Netflix’s director of independent film. “It’s usually that sense of ownership — I found this, I want to share it with my friend, I want to watch it again and again.”

As always, the company remains tight-lipped about ratings but did provide a single statistic — one in three viewers has re-watched “The Kissing Booth,” a figure 30 percent higher than the site’s average rate. That mirrors the story’s success on Wattpad, where it won the community’s 2011 Watty Award for most popular teen fiction. The popularity could be attributed to the demographic of Wattpad users, more than 70 percent of whom are female and 80 percent of whom are millennials or Gen Z. The platform allows writers to upload their stories in installments, using readers’ feedback on each chapter to shape future ones

“I talk about writing fiction as a solitary experience,” says Allen Lau, Wattpad’s CEO and co-founder. “I should add that reading fiction . . . is also a solitary experience. We completely changed that.”

Fervent interest in the story — quantified by millions of reads and thousands of comments — piqued the interest of Random House Children’s U.K., which at the time kept a close watch on Wattpad buzz and signed a three-book deal with Reekles in 2012. (The other books, “Rolling Dice” and “Out of Tune,” also have been published.) Once again, relatability sealed the deal.

“Everyone has a crush on someone that’s slightly older and often for teenage girls, it can be older brothers of your friends,” says Naomi Colthurst, a commissioning editor at Penguin Random House Children’s U.K. “I think it really resonates. It’s very everyday romance.”

Perceptions of this romance hinge on how readers feel about the bad boy trope. Both the book and its close adaptation emphasize Noah’s aggressive and controlling nature, with Elle repeatedly calling him a “violence junkie.” He gets into fights for no reason and warns his male peers to never express romantic interest in Elle. In a particularly disturbing — then quickly forgotten — movie scene, Lee finds Noah cleaning a cut on Elle’s head and asks his brother if he is the one who inflicted the injury. (He isn’t, but the question itself speaks volumes.)

That certainly didn’t stop anyone from buying the book, which Random House Children’s U.K. published in 2013. Komixx co-founders Cole-Bulgin and Ed Glauser watched Reekles’s audience grow from afar and eventually met with Reekles and her father in late 2014 over tea at Paddington Station to ask if they could buy the rights to “The Kissing Booth.” Their business strategy at the time had been to find scripted young-adult projects, Cole-Bulgin says, and it made sense to select one with a built-in online following, given the likelihood that the adaptation would end up on a streaming service.

The next step was to find a screenwriter who could channel a 15-year-old’s voice, and Komixx went with Vince Marcello, known for writing the 2013 Disney Channel hit “Teen Beach Movie” and its sequel. Despite being a grown man, Marcello says he felt an instant connection with Reekles, who provided input on the script and recalls texting her father, “This guy writes my book better than I do.”

Having been a young person during the John Hughes era of rom-coms, Marcello recognized the cinematic influences of those films on “The Kissing Booth” and related to the plot itself.

“My best friend was a girl growing up all through middle school and high school,” Marcello adds. “We were Lee and Elle, totally tied at the hip. . . . When we started to date other people, there were strains on the friendship and fights. It was real.”

Conflict in “The Kissing Booth” culminates in a fight between the best friends after Lee finds out Elle has been lying about dating his brother. Though Elle becomes the object of the brothers’ fighting, Netflix’s Bricke says the character exhibits “more agency and ownership of her story than some of the female protagonists” of Hughes’s movies. This mix of classic and contemporary sold Bricke on the project when Marcello, Cole-Bulgin and Glauser pitched it to Netflix in early 2016.

“It was a sincere story,” he adds. “We really liked the fact that one side of the triangle was a true, real friendship between a boy and a girl. That felt like a fresh aspect.”

“The Kissing Booth” also catered to a unique age group nestled between Disney Channel viewers and young adults who opt for slightly more mature content, like “13 Reasons Why.” Despite this, Bricke says, nobody expected the movie to take off the way it did — not even Reekles, who now works full-time in IT and remained relatively hands-off throughout production.

“It was weird, actually seeing the final cut of the movie,” she says of the film’s emotional scenes. “I watched it with a beaming smile on my face, knowing that if I hadn’t written it, I would probably be crying.”