Genevieve Morgan begins an interview not with an apology, but a statement of fact:

“There are no vampires in my book.”

The Portland writer is speaking of her young-adult fantasy, “The Fog of Forgetting.” Islandport Press in Yarmouth releases the book July 17, and Morgan celebrates with a hometown party and book-signing from 5 p.m. to 7 p.m. July 28 at Urban Farm Fermentory, 200 Anderson St.

Released under her writing name, G.A. Morgan, “The Fog of Forgetting” is an adventure fantasy set in Maine and based on Morgan’s summer experiences as a kid on Mount Desert Island. It has a fast-moving plot, a reluctant hero and what Islandport children’s editor Melissa Kim called “an inner adventure” that draws on past civilizations and global cultures.

“It’s not a cliché, young-adult book,” said Kim, who vetted the book with her 9-year-old son, a voracious reader. He liked it.

“A lot of books fall into a standard, fill-in-the-blanks kind of plot. I liked ‘Fog’ because I thought it was not formulaic,” Kim said. “It has a lot of characters that readers can identify with, and it’s not fluffy. It has a lot of substance to it.”

On a summer day, five kids go for a boat ride, get lost in the fog and end up on the mysterious island of Ayda, far from the Maine coast. They find themselves in a centuries-old battle among four ancient realms and must learn to harness the forces of earth, fire, water and air to find their way home.

“The Fog of Forgetting” is the first in a trilogy, Morgan said.

“I started telling this story to my kids when they were little,” she said. “It just grew and grew in my imagination.”

Her boys are 17 and 14 now, and both attend Portland High School. They’re not in the book, but it’s easy to detect their influence in Morgan’s characters and plot development, which centers on siblings and their summer adventures in Maine.

Morgan left a lot of herself in this book, too.

She grew up in Manhattan and spent summers in Maine. Her mother was raised on a York County farm, and her parents bought a house on Mount Desert. She has spent every summer of her life on Mount Desert and has lived in Maine since 1998. Now 47, she graduated from Bowdoin College in 1989.

While “The Fog of Forgetting” marks Morgan’s debut as a novelist, the book is not her first. She has written nonfiction under her full name, including a book for teens called “Undecided: A Guide to Navigating Life after High School,” released this spring by Zesk Books.

Before moving to Portland, she was managing editor of Chronicle Books, and she has written for editorial and commercial clients, including Hay House Publishers, Bon Appétit and Maine magazines.

What she remembers most about coming to Maine as a kid is the lack of fear. Manhattan in the 1970s was a scary place. Maine was not. Whether on her grandmother’s farm in York County or the family house up the coast, Morgan found a connection to nature, a sense of magic and a different level of excitement than what she was accustomed to in New York.

“Maine was so different from my everyday experience,” she said. “I learned to shed the fear of the city when I came to Maine.”

In many ways, this book represents that freedom. It is full of imagination and adventure. It is fantasy, but based on Morgan’s reality.

For Islandport, “The Fog of Forgetting” represents a leap. The press has published a few titles that qualify as young-adult fiction. But this is Islandport’s first book in the adventure/fantasy realm and its first national marketing effort with a young-adult title.

Generally, the publisher has concentrated on books rooted in the essence of New England.

“It’s the first time we are looking more broadly, moving beyond our previous titles that have a more regional focus,” Kim said. “I’d like our children’s/YA titles to be seen as more than just New England-based, and this is a big step in that direction.”

Barnes & Noble has placed a large advance order for “The Fog of Forgetting,” suggesting that Islandport will reach a wide audience with this book.

Writer Annie Barrows, for whom Morgan worked while at Chronicle, said the young adult label is misleading. She thinks Morgan’s debut novel is appropriate for readers of any age.

“I think it’s disingenuous to call it young adult. We all love Harry Potter. Everybody is reading young adult fiction. Everybody,” said Barrows, who is best known for the “Ivy and Bean” series of children’s books. “I think young adult has come to almost be a term for a book that has young characters.”