Year 101 Rihoko finally gets to start her apprenticeship in space travel and live separately from her brother, whom she didn't get along with. But then an intruder causes their spaceship to crash onto Earth with no way to go back anymore. After the crash a huge shield appeared, trapping everyone inside it. Soon after, many people got an unknown disease. Society splits in two, leading to many civil wars between the mutated and the humans. Yet, admit the chaos, Rihoko is happier than ever.

• Sci-fi