The Delta Codex - by Deva Fagan (Hardcover)

Book Synopsis

A girl whose subconscious contains dangerous ancient knowledge finds her voice in this gripping middle grade sci-fi fantasy perfect for fans of Diana Wynne Jones and Scott Reintgen.

Is there safety in silence?

In the city of Danak-Tol, children known as codexes are chosen to safeguard echoes--fragments of ancient knowledge too valuable to destroy but too dangerous to use. Forbidden to speak lest she accidentally release her echo, codex Delta lives a lonely life. Still, she knows she must obey the wardens' strict rules to keep her home safe from the vicious beasts, heretical Scrappers, and toxic blood storms that lurk beyond the city walls.

But when Delta breaks her vows to help a young girl escape a blood storm, she begins to have strange dreams, which lead her to question everything she knows to be true about herself and her city. To find answers, Delta must journey to the one place she most fears: the wasteland beyond the walls of Danak-Tol.

Together with her small but feisty mechanical companion Flick, Delta dares the perilous ruins of a long-abandoned skyship, the gullet of a ravenous sphincter worm, and even befriends a young Scrapper named Drii. But all these adventures only lead to more questions. What is the true danger that threatens her entire planet--is it really her echo, or is it the silence that has imprisoned the truth for so long?

Review Quotes

* "In this gripping science fiction thriller, Fagan reiterates her strength as a masterful world builder. . . . Fans of Scott Reintgen and Fagan's earlier works will eagerly embrace this thought-provoking, emotionally resonant novel."--School Library Journal, starred review

"It's an exquisitely crafted sci-fi mystery, and though suspense and action abound, it makes time for humorous asides and moments of wonder. An extensive history and mythology flesh out the fascinating world, and Delta's internal journey feels as profound as her external odyssey. An exhilarating examination of the power of stories, truth, and kindness."--Booklist

"Readers will be drawn in by the warm, wholesome cast of characters. A hopeful, exciting, and action-packed adventure."--Kirkus "3/1/26"

"[E]lectric . . . . Concise, economical storytelling and steady pacing mold a vast dystopian world whose charismatic leads evoke protective warmth from the jump."--Publishers Weekly "1/26/26"

About the Author

Deva Fagan writes fantasy and science fiction for all ages. When she's not writing, she spends her time reading, doing geometry, playing video games, hiking, and drinking copious amounts of tea. She is the author of several books, including Rival Magic, Nightingale, The Mirrorwood, A Game of Noctis, and The Delta Codex. She lives in Maine with her husband and their dog. You can find her online at DevaFagan.com.