In the distant future, a gigantic energy mass called the "Star of Destruction" suddenly appears near Mars. Its presence causes abnormal weather and tectonic plate shifts on Earth. As resources become scarce and populations have nowhere to go, conflicts erupt worldwide. This, however, is merely an omen of things to come.

Only a hundred years remain for humanity. They plan to evacuate the planet to evade its doom. Two projects are drafted to meet that end.

First is the establishment of Earth's Unified Government, which will allow the project to be implemented. Evacuating Earth becomes a top priority, and the order of "sacrificing the few to save the many" is implemented. Authoritarian rule controls the masses. Armed force oversees states and non-governmental organizations that oppose the new world order. The overwhelming military power maintains order regarding race, religion, food, energy, etc.

The second is the "Felix Project," which will serve as the foundation for the exodus plan. With only 100 years left, humanity needs to build a spaceship to leave the planet and acquire the technology to survive in the vacuum of space for a long time. They decided to create "Felix," genetically modified people with extraordinary intelligence and longevity. These "superhumans" will be able to complete the seemingly impossible project.

99 years pass.
A lone female Felix, Sion, has served her role as the central figure in the Earth Evacuation Project. With her job completed, Sion wishes to spend her remaining time quietly on the abandoned Earth. A young man, Ryo Haruna, from the unified military, is deployed to her side to protect and keep her in check.

Their meeting sets the story in motion.
The final love story on Earth.

[Translated and edited from official site]