In a world that is enveloped in snow and has canopies reaching to the sky, two people from different communities make an encounter that changes history.

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. While out hunting, young Kaina stumbles upon an unconscious girl who's floated up from the surface. The discovery of this trespasser brings new hope for mankind's future-and unimaginable danger!.—Crunchyroll

Humanity is facing extinction. In a snow-covered world where water has become scarce, the last habitable lands are located at the feet of gigantic Orbital Trees scattered about the desolated Earth. According to a legend, there exists a sage who knows the secret to producing abundant quantities of water to save mankind. Ririha, the princess of Atland, uses an organic hot-air balloon to climb to the top of an Orbital Tree in hopes of meeting her country's savior. Once she reaches the Canopy-an area that appears to be an infinite window of transparent ice-she meets Kaina, one of the last men alive on the Canopy. However, she can not find the man she was looking for. Unable to return by herself to her country, the princess finds a helping hand in Kaina, who is eager to explore the surface world that he thought was empty. As Kaina learns about the war against Ririha's country, the antagonistic technologically advanced nation Valghia, and other perils of the surface, he realizes that his escorting mission will prove more difficult than he imagined.—MAL Rewrite

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.—Bilibili TV