Making a grab for the fan bases of “The Hunger Games” and “Game of Thrones,” the new young adult novel “The Queen of the Tearling” throws us into a magical, medieval world set not in the past or a fictional universe, but in the distant future of our own world.

This twist may be what attracted “Harry Potter” star Emma Watson, who announced she’s signed on as both executive producer for the film adaptation of the book — the first in a trilogy by debut author Erika Johansen — and its star. “I was desperate to hate it,” joked Watson, who conceded she couldn’t put the book down. Having sworn she’d never do another franchise, her interest is a gigantic compliment. Out Tuesday, the book’s rights were purchased by Warner Bros. a year ago.

“Tearling” is, indeed, a gripping read, though not without a few overly familiar plot devices.

Kelsea is a royal teen who’s been hidden all her life with adoptive parents; her mother, the queen, is dead, and her kingdom, the Tearling, is under the thumb of a neighboring country called Mortmesne, ruled by a supernaturally enhanced monarch known as the Red Queen. Besides sharing a name with the “Alice in Wonderland” character, the Red Queen recalls Melisandre of “GoT” with her mystical visions and dependence on human sacrifice.

On her 19th birthday, the “plain,” bookish Kelsea is summoned to assume the throne, a job for which she feels deeply unsuited: “She had no idea what to do. How was she to command anyone?” Her country is badly in need of new leadership: Its current ruler sends the Red Queen monthly shipments of peasants to be used as slaves in exchange for the Queen not invading. These deliveries are referred to as “tributes,” a term that will resonate loudly with anyone who’s read “Hunger Games”; ditto, the unlucky citizens’ selection by lottery.

If you can get Katniss out of your head, though, Johansen spins an engaging story with plenty of action, a sometimes-startling amount of gore and intriguing characters. Chief among them is a mysterious woodsman known as the Fetch, who rides with a mask: “A harlequin, but much more sinister, awful in some way that she couldn’t put her finger on.” He brusquely challenges Kelsea to be a better queen than her mother, leaving her unsettled — and a little infatuated.

Johansen wisely leaves us wanting to know more about what exactly happened to the world in an event referred to only as “The Crossing.” Jarringly, among the descriptions of castles and soldiers and peasant villages, are references to cities, computers — even the works of J.K. Rowling, whose dusty volumes are part of Kelsea’s secret library. With Watson’s stamp of approval, the Rowling connection is cemented — as is, I’d guess, the success of this franchise.