The Apollo program, implemented by America’s National Aeronautics and Space Administration (NASA) from 1961 to 1972 A.D., carried out humanity’s first manned spaceflight mission to the Moon. The Apollo spacecraft, which made a landmark achievement in the history of humanity’s space endeavors, traveled from Earth to the Moon – a journey of about 380,000km – in just over 100 hours.
100 hours is roughly four days. Surprisingly, flight time to the Moon was quite short even in the world of the 20th century A.D.
On a smaller scale, but still speaking of a sense of time, Japanese express messengers in the Edo Period could travel from Edo to Kyoto in merely three or four days. Likewise, the famous tale of Chūshingura recounts how the news of an Akō lord committing seppuku was delivered from Edo to Akō (the southwestern part of present-day Hyōgo prefecture) within five days, by men carrying a palanquin.

In modern times, it is said that Earth has been getting gradually smaller thanks to the technologies developed throughout the years, such as steam trains, automobiles, fast ships, high-speed railways, and airplanes. But it is surprising that such closeness can be felt even in the sense of distance between Earth and the Moon.
In the Universal Century era, the distance from Earth to a space colony might feel even smaller, especially considering the massive advances in technology.
Despite this short distance, there is a vast chasm between the hearts of those who live on Earth, and those who have emigrated to space. That is the ambience of the Universal Century.

The new era known as the Universal Century is abbreviated as U.C.
U.C.0001 The new era begins with the start of space emigration.
U.C.0027 The first permanent lunar city, Von Braun, is completed.
U.C.0040 40% of the total population has emigrated to space.
U.C.0041 The asteroid Juno (Luna II) is placed in the Moon’s orbital path.

The area of humanity’s influence, enlarged by this emigration, becomes known as the Earth Sphere.

More than half a century has passed since countless people began moving from Earth to the man-made habitats known as space colonies.
During this time, the number of space colonies housing these emigrants has steadily increased, and the colonies have grouped together into Sides that operate with some degree of autonomy. However, much of the political framework remains under the control of the Earth Federation government, which is the basis for the sovereignty claimed by those living on Earth.

It can’t be denied that this has given the people of Earth a certain sense of superiority over those living in space.
Without sovereignty, the people of space have remained continually vulnerable to economic demands and governmental oppression from the Earth side.
Perhaps it was inevitable that this one-sided state of affairs would create a variety of overt and covert frictions between the parties, and bring about a “power” that would attempt to resolve the situation.

This is the era in which the man called Zeon Zum Deikun appeared.

He preached a certain ideology to the people living in space.
This ideology was extremely radical and progressive, and it captured the hearts of many of the people of space.

The time is now just 10 years after Deikun’s first appearance. With his sudden death, a drastic transition is about to begin.
Caught up in the tumult are Deikun’s orphaned children, Casval and Artesia. The young siblings will part with those they love, and make a variety of journeys between the space colonies and Earth.

The great sense of distance the two children feel between the Moon, Earth, and space colonies, is perhaps similar to the sense of distance when we are separated from our loved ones.
They may feel even more cruelly distant than the Moon, as viewed from Earth by the people of the pre-Apollo era……