A short walk during a school trip sends Ren tumbling into a world that shouldn’t exist. Beneath towering ferns and glowing violet mushrooms lies Atheria, a hidden village of animal-like people who have never seen a human. To some, Ren is a curiosity. To others, he is something to fear. But their queen sees in him a hope her people are running out of.

Behind the forest’s wonders lies a troubling legacy: a human who arrived long ago, the experiments that changed its inhabitants forever, and a sacred secret that can no longer sustain them. As Ren builds friendships and discovers unfamiliar customs, his search for a way home becomes entangled with Atheria’s uncertain future. His choices will shape whom he trusts—and what he is willing to do for a world he barely understands. He fell into their world by accident. Now they’re asking him to change its fate.