Each chapter is summarized as follows: The Diver's Adventure - The protagonist, Nimo, got his diving license and began his diving adventure. - He began to explore the underwater world and encountered all kinds of strange creatures and dangerous situations. Undersea City - Nimo discovered an underwater city filled with all kinds of high-tech equipment and cultural relics. - He went deep into the underwater city and explored the buildings and systems inside, discovering a huge empire. Mysterious Creature - In the underwater city, Nimo met a mysterious creature that had deep thoughts about human civilization. - This creature brought a new technology that allowed Nimo and his companions to better understand the underwater world. Undersea War - The underwater city became the focus of a huge war. Both sides were fighting for the city and the resources inside. - Nimo and his companions became the victims of the war. They had to do everything they could to protect themselves and their homes. The Last Adventure - Nimo and his companions decided to leave the underwater city to continue their adventure. - Before they left, they discovered some precious cultural relics and technology that would become their future wealth. A New Adventure - Nimo and his companions encountered some new problems and challenges on their expedition, but they were determined to overcome them. - They continued to explore the more mysterious underwater world and discovered some exciting secrets. Returning to Land - Finally, Nimo and his companions returned to the mainland and began a new life with new knowledge and experience. - They were determined to protect the sea world and prevent similar tragedies from happening again.