In a city of shimmering pearl that floats on the endless sea of the sky, ten-year-old Elara has only ever known a life of light, music, and gentle breezes. Aethel is a marvel, held aloft by a power forgotten to time. But the magic is fading.

When the city’s great Sky-Lamps begin to dim and terrifying tremors threaten to send her home plummeting into the unknown Groundlands below, Elara discovers a secret that the city Elders have long kept hidden. A single, iridescent feather leads her into the heart of the ancient Whispering Spire, revealing a desperate truth: Aethel is dying, and the only cure lies in the forbidden world below the clouds.

Guided by a celestial map and a forbidden alliance with a banished inventor, Elara must leave her world behind. Her journey will take her through forests of luminous mushrooms, across a river of forgotten memories, and past slumbering earth giants. But a malevolent shadow, the physical embodiment of Aethel's decay, hunts her every step, and a traitor works from within the city to hasten its demise.

Armed with little more than a fragile glider, a half-remembered lullaby, and a courage she never knew she possessed, Elara must race against time to find the legendary Sunstone. Can one small girl brave a world of impossible wonders and terrifying dangers to reignite the heart of her home before it is lost forever to the sky?