National Geographic children’s books have always had loyal readers. Animal lovers. The geography obsessed. Those who must read every “Weird but True” book in the franchise.

“Those are the knowledge seekers, the fact-hounds,” says Jennifer Emmett, vice president for content at National Geographic Kids and Family. “We also really wanted to bring in kids who experience content a little different and are more attracted to story and want to be immersed in a world.”

So National Geographic took a leap and launched a middle grade series of “fact-based fiction.” The first of a planned seven-title series, Explorer Academy: The Nebula Secret, was released this month. Written by Trudi Trueit, this series combines real science with a fictional adventure plot.

“We wanted to pull kids in with immersive adventure stories and developing characters and get them hooked on stories that will continue and they can feel a part of,” says Emmett.

National Geographic is hoping educators will use the fiction series as part of their teaching just as they have the many nonfiction series over the years. There is an “ Educators Guide ” with questions, activities, and lesson suggestions, as well as applicable curriculum areas such as reading comprehension and retention, critical thinking, ethics, and vocabulary. There is also a complementary multimedia campaign with videos showing real-life science and animated webisodes.

Each book ends with a “The Truth Behind the Fiction” section that discusses the real science used in the book and spotlights the real-life work of National Geographic explorers.

The new division meant a new way of working for the entire staff. Becky Baines, the editor of the series, laughs when asked how different this series was compared with the many nonfiction titles she has edited over the years.

“I didn’t realize until I started how much I didn’t know,” says Baines. “With nonfiction, I’ve been doing it for 14 years now. You have to have a good editorial ear, you have to know what’s appropriate for a certain age; then you go and fact-check.”

Fiction, however, blurs the lines. Baines says, “We needed to decide where the factual line ends and the fictional line starts and how to decipher that for kids. It actually took a huge team of people. I’m working with an outside project editor who has done fiction for a long time. I have several people in house reading behind me.”

And Baines has nothing but praise for Trueit, who is already working on the fifth book of the series.

“Her ability to weave in the science and keep the narrative so intriguing and get deeper with the mystery is completely amazing to me,” she says.

The publisher also has a focus group of about 2,000 children readers who provide feedback on content across their publications. Their response after reading Nebula Secret had nothing to do with fiction vs. nonfiction, however. Their big takeaway: the book needed more prominent girl characters.

While the main character is still a boy named Cruz, who left his family in Hawaii to train at the elite Explorer Academy in Washington, DC, there are now female Explorer Academy members who play bigger roles throughout the first novel.

In the end, it’s about inspiring kids in a new way.

“We want kids to feel like they can be a part of the Explorer Academy, and they can learn from the National Geographic explorers, and they can be inspired to be explorers themselves,” says Emmett. “That’s really our ultimate goal. We care about training the next generation of explorers to be stewards of the planet and make sure we’re all in good hands."