For as long as Fei can remember, there has been no sound in her village, where rocky terrain and frequent avalanches prevent residents from self-sustaining. Fei and her people are at the mercy of a zipline that carries food up the treacherous cliffs from Beiguo, a mysterious faraway kingdom. When villagers begin to lose their sight, deliveries from the zipline shrink and many go hungry. Fei's home, the people she loves, and her entire existence is plunged into crisis, under threat of darkness and starvation. But soon Fei is awoken in the night by a searing noise, and sound becomes her weapon.