There's a man aged 93 years. He was born in the "City in the water" and lived there all his 90-plus years. You can see him always sitting under the zelkova tree beside the lake. However, he doesn't look at the beautiful lake. Instead, he looks the opposite side, where hills, walls and roads are. There's a quizzical eye of a man, observing him. One year passes. Seasons change. One day, the old man stares at a certain point in the lake, for the first as well as the last time. That was the location where the house he had been born in was. And he happens to get hospitalized soon afterwards. Then the exploration of the 'City in the water' began based on the old man's story.