After humanity's extinction, a pencil case left behind by the civilization of the past is said to be able to restart human civilization. The four remaining members of humanity set out on a journey to save it. They visit many planets, each with its own story, and encounter alien civilizations, sometimes befriending them and sometimes coming into conflict. Along the way, they expand their knowledge. But how will they find the pencil case that was their original goal and use it to save human civilization?
Five-star support! It gave me the feeling that the author's writing style was immature. I don't know if it is for middle and high schools.