Long ago, there was a large village by the Songhua River called Dagashan. There was a man named Lao Shunde who often transported local mountain goods to the capital thousands of miles away for sale and was a well-known capable person in the area. Over time, many people in the capital knew him, and often someone would ask him to deliver a letter or bring something. He always agreed and never made a mistake.

One day in the capital, Lao Shunde sold all his local mountain goods and was preparing to return home. At this time, a person found him and asked, "Are you Lao Shunde from Dagashan?"

The person was dressed like an official and seemed to have a high position. Lao Shunde hurriedly replied, "I am Lao Shunde from Dagashan. What can I do for you, sir?"

The man said, "My surname is Yu, and my hometown is also in Dagashan. I would like to ask you to deliver a letter to my home. Is it okay?"

Lao Shunde patted his chest and said, "No problem. I guarantee it will be delivered."

The man was very grateful, handed a letter to Lao Shunde, and left after expressing his gratitude repeatedly.

When Lao Shunde returned to Dagashan, without even taking a break, he was busy delivering the letter to the Yu family. There were two families surnamed Yu in Dagashan. Lao Shunde came to the first one, which was a young couple. As soon as he entered the threshold, he asked, "Little brother, do you have relatives in the capital?"

The young Yu scratched his head and said, "The capital? Relatives?"

"Yes, and he's an official. He sent you a letter."

The young Yu thought for a long time and said, "When I was old enough to remember, my family had no relatives. Later, I came here by begging. If I had relatives who were officials, could I still live such a poor life?"

Lao Shunde thought carefully. The official who asked him to deliver the letter said that his hometown was in Dagashan and must be an old resident. This young Yu only came to Dagashan a few years ago. It was definitely not this Yu family. He had made a mistake.

The second Yu family was an old bachelor and an old resident. He was quite old. Needless to say, the family letter was for him. As soon as Lao Shunde saw the old bachelor, he smiled and said, "Congratulations. Your relatives in the capital sent you a letter." Saying that, Lao Shunde handed him an envelope.

The old bachelor took the letter, looking puzzled. He stared blankly for a long time and said, "You are mistaken. I have no relatives in the capital. Let alone in the capital, I don't have a single relative even in the neighboring villages. You must be mistaken." Saying that, he returned the letter to Lao Shunde.

Every time Lao Shunde delivered letters and books for others, he could do it successfully and everyone was happy. But this time, no one accepted the family letter. There was nothing written on the envelope, and it was not good to open it and read. This really puzzled him. Since he was entrusted by someone, he couldn't break his promise. Lao Shunde thought that since neither of the two Yu families in Dagashan was the right person, maybe the recipient had left Dagashan and gone elsewhere? As long as the person was alive, he would do everything possible to deliver the family letter to them. So, Lao Shunde asked everyone he met and inquired everywhere if there were any other Yu families in Dagashan before. But all he got were shakes of the head. For many days, there was not a single clue, which made him so worried that he couldn't eat or sleep well.

One day, an old lady told Lao Shunde, "When I was young, I heard that there was another Yu family in Dagashan, living by the Blackfish Pool at the village head."

The Blackfish Pool was a large pool at the village head, shining white and bottomless. It was said that there was a one-eyed blackfish spirit inside, fierce and cruel, that ate people without spitting out bones. Usually, the blackfish spirit was silent, but when it was windy or rainy, it would create trouble, causing the river to flood,Flooding the road, and making Dagashan an isolated island.

Lao Shunde asked, "What happened to that family later? Were they harmed by the blackfish spirit?"

The old lady said, "I don't know. If you want to know these old stories, you have to ask Second Master Zhang. He is old and knows many things."

Second Master Zhang was over a hundred years old. All the stories of Dagashan were in his heart. Now he lived in the mountains, watching the old mountain temple and rarely returned to Dagashan. In order to fulfill the task entrusted to him by others, Lao Shunde decided to find Second Master Zhang to find out the truth. The next day, he left home with the letter. Afraid of losing the letter, he stuffed it into his wide tobacco pouch.

To get to the old mountain temple, one had to pass by the Blackfish Pool. It was a narrow path overgrown with weeds, winding and rough. The edge of the Blackfish Pool was full of dark elm trees, looking gloomy. When Lao Shunde got here, he couldn't help feeling flustered. Somehow, he tripped over something under his feet and fell with a "thump" by the water. His heart pounded even more. He turned over and got up, running forward without looking back.

Lao Shunde crossed mountains and hills. After an unknown amount of time, he finally arrived at the old mountain temple. Meeting Second Master Zhang, he explained his purpose. Second Master Zhang twirled his silver beard and said, "If you really can't find the person, open the letter and take a look. Then you'll know everything. If you're worried, I'm willing to be a witness in the middle." Lao Shunde thought that this was the only way and reached into his bosom to take out the letter. Unexpectedly, his bosom was empty. Both the tobacco pouch and the letter were gone.

It didn't matter if the tobacco pouch was lost, but losing someone else's family letter was a big deal. Lao Shunde was so worried that his throat was parched. Second Master Zhang comforted him not to worry and accompanied him to look for it along the way they came. They found the old elm tree by the Blackfish Pool, at the place where he fell. The tobacco pouch was intact there, but the letter inside was gone. Lao Shunde held the tobacco pouch and couldn't say a word: "This, this... The letter was clearly in the tobacco pouch. How could it be gone? It's like seeing a ghost..."

Second Master Zhang stood under the old elm tree, facing the Blackfish Pool with a solemn expression. He said, "You have already delivered the family letter."

Lao Shunde was greatly puzzled: "The letter was clearly lost. How can you say it was delivered?"

Second Master Zhang said, "Let me tell you a story."

Speaking of the Blackfish Pool, it was even older than Dagashan. A long time ago, whenever it rained and the water rose, a single-log bridge would appear on the road. People from Dagashan could go out by crossing the single-log bridge, and people from outside could also come in. The villagers liked the Blackfish Pool very much and often came here to catch fish and take baths. The children especially spent all day in the Blackfish Pool and were reluctant to go home. There was a Yu family living by the Blackfish Pool. The old couple had a daughter in their old age and regarded their daughter, Shuixian, as the apple of their eye. When Shuixian grew up to be sixteen or seventeen years old, she became very beautiful. Many people came to propose marriage, but Shuixian didn't like any of them. No one expected that Shuixian didn't get married but was pregnant, and her belly grew larger day by day. This was a scandalous event and drew the condemnation of the people of Dagashan. The old couple had been honest and upright all their lives and couldn't bear this. They forced Shuixian to tell who the adulterer was, but Shuixian wouldn't say. Soon, the Yu family left and went far away.

Lao Shunde interrupted, "Even if the Yu family moved away, it can't be said that the letter was delivered. I can't do such a deceptive thing!"

Second Master Zhang said, "That family letter wasn't written to the Yu family at all."

Lao Shunde was even more confused.

Second Master Zhang continued his story: After that, every night when it was quiet, people often saw a strange young man in black wandering alone under the old elm tree, sometimes emitting a desolate and sad crying sound, which lingered over the Blackfish Pool for a long time. Later, there was a heavy rain, and the water in the Blackfish Pool rose again,Flooding the road. A single-log bridge appeared again. A villager from Dagashan crossed the single-log bridge and sat at the bridgehead. While smoking, he pointed at the collapsed house of the Yu family and said, "Shameful! You have disgraced the people of Dagashan!" Then, he knocked his tobacco pipe hard on the single-log bridge, sending ashes and sparks flying. Suddenly, the single-log bridge rolled over and threw the villager into the Blackfish Pool. It turned out that the single-log bridge was actually the back of the blackfish spirit. The villager's tobacco pipe just hit the blackfish spirit's eye, and since then, the blackfish spirit has become one-eyed.

When the story reached this point, Second Master Zhang said with emotion, "Now I understand. The blackfish spirit was originally very kind. Whenever it rained and the water rose, he used his body to build a bridge for people. He fell in love with the girl Shuixian from the Yu family. After they fell in love, what they got was slander and harm, so he became fierce... I heard that Shuixian later gave birth to a child, a boy, who was talented and promising, passed the imperial examination, and became a high-ranking official in the capital. The family letter you delivered was written to this 'fish' family."

Lao Shunde had traveled far and wide for most of his life but had never encountered such a strange thing. So what message did this family letter want to tell the blackfish spirit? Lao Shunde couldn't guess no matter how hard he tried.

Soon, Lao Shunde came to the capital again. He heard that a wonderful story was being circulated all over the capital: An old lady was awarded the title of Imperial Order of Merit by the emperor because she gave birth to a general who had made great military achievements and protected the country. The surname of that general was very strange. It was "Fish"...