It is thirty years after the failure of the Space Colonization Program. Humanity is nearly extinct. A perpetual and deadly Rain falls on the Earth. Men known as "Junkers" plunder goods and artifacts from the ruins of civilization. One such Junker sneaks alone into the most dangerous of all ruins—a "Sarcophagus City." In the center of this dead city, he discovers a pre-War planetarium. And as he enters he is greeted by Hoshino Yumemi, a companion robot. Without a single shred of doubt, she assumes he is the first customer she's had in 30 years. She attempts to show him the stars at once, but the planetarium projector is broken. Unable to make heads or tails of her conversation, he ends up agreeing to try and repair the projector... (Source: Steam)

In A.D. 2031, humans are enjoying a prosperous existence until strange life forms called Hardians appear. They suddenly begin to multiply and assault the human population. As a countermeasure, mankind organizes the N.I.D.F. to investigate the Hardians and protect themselves. A fighter pilot, Aiba Shu, begins to become involved in the battle against the lifeforms. Rurika Yuno, one of Earth's foremost scientists, investigates the Hardians and hears rumors about the "Book of a Dead Man." What is the secret of this tome, and what relation does it have to the Hardians? Now, the fight for mankind's survival begins. (Source: AnimeNfo)

After the murder of their parents, 11-year-old twin brothers Thor and Rai Klein are sent away from their home planet. They find themselves awakening on the terraformed planet of Chimaera, where carnivorous plants dominate and the few humans who live there are divided into four groups known as "Rings." Soon after, they meet a young man by the name of Zagi, and the twins learn that only the "Jyu Oh Sei"—the one who conquers these four Rings—is allowed to leave the planet. Driven by the desire to return home and discover the truth behind the death of his parents, Thor resolves to survive in the harsh, merciless environment of Chimaera. However, he quickly learns there is more than meets the eye in this strange ecosystem. As Thor is swept up in the politics that entangle the Rings, he uncovers more about his parents' murder, and ultimately, humanity's fate as a whole. [Written by MAL Rewrite]

After the murder of their parents, 11-year-old twin brothers Thor and Rai Klein are sent away from their home planet. They find themselves awakening on the terraformed planet of Chimaera, where carnivorous plants dominate and the few humans who live there are divided into four groups known as "Rings." Soon after, they meet a young man by the name of Zagi, and the twins learn that only the "Jyu Oh Sei"—the one who conquers these four Rings—is allowed to leave the planet. Driven by the desire to return home and discover the truth behind the death of his parents, Thor resolves to survive in the harsh, merciless environment of Chimaera. However, he quickly learns there is more than meets the eye in this strange ecosystem. As Thor is swept up in the politics that entangle the Rings, he uncovers more about his parents' murder, and ultimately, humanity's fate as a whole. [Written by MAL Rewrite]