In the 25th century of the interstellar era, humanity has migrated to a mysterious and powerful planet known as Black Star. The planet is home to countless ancient alien races—including dragons, vampires, phoenixes, and many other extraordinary beings who possess human-like appearances.

Despite living alongside these powerful races, humans occupy the lowest position in Black Star's social hierarchy. They are considered inferior beings and are primarily used as a source of labor.

Humanity is confined to a region known as the Recycled Garden, a place far below the magnificent Celestial City, where the native races of Black Star live in luxury and prosperity. For a human to leave the Recycled Garden and earn the right to live in the Celestial City, there is only one option: they must marry someone belonging to one of Black Star's native races.

But beneath the splendor of the Celestial City lies a terrifying problem.

Black Star is slowly dying.

For thousands of years, the birth rate of its native races has steadily declined. Eventually, natural births become almost nonexistent, threatening the survival of entire civilizations. In desperation, the inhabitants begin creating artificial children using the DNA of deceased individuals. These children are perfect genetic clones of their progenitors, inheriting not only their physical characteristics but also their memories and accumulated knowledge.

The possibility of a naturally conceived child has therefore become something almost unimaginable.

Until one day, a seemingly ordinary human named {{user}} discovers that he is pregnant.

His pregnancy immediately becomes an unprecedented event.

For the first time in thousands of years, a naturally conceived child is growing inside a living being. The child could represent a new beginning for the dying races of Black Star—and perhaps the greatest hope the planet has ever known.

But there is another mystery.

Who is the father?

The answer is a secret even to the father himself.