“It’s been a real-life 21 Jump Street in south Florida,” Chappell—a Florida native who now lives in New York City—says, relating a news report about a teenager caught up in the sting after he’d fallen in love with an undercover female police officer and “wanted to impress the girl” by buying drugs. While Narc contains all the elements of both police procedurals and thriller novels, what most intrigued Chappell was exploring the complex universe of high school social hierarchies. Before he became entangled with the Miami police, Foster describes himself as “human wallpaper,” a stoner who spent much of his time alone, smoking pot, playing video games, and performing street magic.

The plot has a “Cinderella element” to it, Chappell says. In his quest to find the high school drug dealer, Foster begins infiltrating different social cliques, attending parties and socializing with “the cool kids.” By pretending to be extroverted and self-confident, Foster actually does become both—and likes the person he becomes, despite the moral implications of a boy on the cusp between childhood and adulthood performing an adult’s job. Carrying out his assignment of deception, Foster learns that he is not the only student pretending to be someone he or she is not. “Pretending is a survival mechanism for some kids,” Chappell explains. “There’s the funny girl who hides in the bathroom and cries. Or the popular girl who is a cutter.”

Narc is Chappell’s second YA novel. Her debut book, Total Constant Order, which centers on a teenager with obsessive-compulsive disorder, was published by HarperTeen in 2007. “Teenagers are the most interesting people on the planet—I love being in that world,” says the author, a former professor at Miami International University of Art & Design, describing herself as “forever” a teenager trapped in an adult’s body.