A world blanketed in an endless and ever-growing ocean of snow.

The people eke out a living, either huddled around the roots of enormous trees dotting the surface, or high in the canopy, which spreads over the planet's atmosphere.

A chance meeting between Kaina, a youth from the canopy, and Liliha, a young woman from the surface, sets off a chain of events that will change the fate of the world.

[Source: FujiTV]

Humanity’s remnants struggle to survive above the planet atop giant orbital spire trees, safe from the danger below. Rendered unlivable, the Great Snow Sea has turned the world into a no man’s land.

In the midst of this apocalypse, Kaina, a boy with the rare ability to read, meets Ririha, a princess from the Snow Sea. During their trip to find the “Great Orbital Spire Tree,” the source of drinkable water, they encounter an autocratic nation, Planato, led by a dictator, Byozan. Byozan controls a weapon called the “Builders” at his convenience and plans to destroy the Great Orbital Spire Tree for what he claims is the sake of mankind. Kaina and Ririha must decipher the lost “written words” together to solve the mysteries of their dying world.

Kaina and Ririha’s journey to change a world heading for destruction begins!

[Source: FujiTV via Anime Expo]