From New York Times bestselling YA author Rebecca Mix comes the first book in a breathtaking middle grade fantasy duology about a young fairy who has always lived in her heroic grandmother’s shadow but now must step up and embark on a quest to save her mother from the ever-creeping mold overtaking their world.

The mold takes all.

Twelve-year-old fairy Canary Mossheart knows this better than most. A few years ago, the mold took her papa, and even her famous, former-chosen-one Gran never found a cure. So when Ary's beloved mama falls ill, Ary decides it’s taken enough. Armed with only a bucket and a prayer, she sneaks out to find a magical, underground lake whose healing waters are straight out of Gran’s adventures.

But when Ary gets there, the lake’s bone dry, and instead of healing waters, she finds a terrifying secret: Her entire world is actually trapped inside a giant terrarium—one they were meant to leave centuries ago. Worse, Gran knew and hid the truth, dooming Ary and her generation to a dying, rotting world.

Now, allied with only her doomsday-obsessed frenemy, a timid pill bug, and a particularly grumpy newt, Ary has one week to unravel the clues and find a way out of the terrarium—or they’ll be trapped for good.

Perfect for readers who loved Brandon Mull's Fablehaven, The City of Ember by Jeanne DuPrau, and Endling: The Last by Katherine Applegate.

A Hidden World with a Dark Secret: Ary’s home isn’t just a village—it’s a giant, decaying terrarium, and the heroic grandmother she trusts has been lying about it for generations.
Unlikely Friendships: To survive, Ary must team up with her doomsday-obsessed frenemy, a timid-but-loyal pill bug, and a particularly grumpy newt.
Eco-Fantasy Adventure: A mysterious and ever-creeping mold has taken Ary's father and now threatens her mother, forcing her on a desperate quest for a cure in a dying world.
A Coming of Age Quest: Stepping out of her famous grandmother's shadow, Ary must find the courage to become the hero her family and her fragile world desperately need.

The Mossheart's Promise

The Mossheart's Promise