During the reign of Emperor Wu of the Han Dynasty, there were frequent wars between the Han Dynasty and the Xiongnu. The two sides sent envoys to the other side several times to spy on military information, and the Xiongnu successively detained more than ten groups of Han envoys. The Han Dynasty was also not easy to provoke, and detained several Xiongnu envoys. In 100 BC, Hou Shan ascended the throne. He had just ascended the throne, the regime was still unstable, if at this time the Han Dynasty sent troops to attack the Xiongnu, the Xiongnu would certainly not be able to fight. Therefore, he said that the Son of Heaven of the Han Dynasty was his elder and returned the Imprisoned Han envoys.
In this regard, Emperor Wu of Han was very satisfied, so he sent The Zhonglang general Su Wu to escort the Xiongnu envoy back to China with a festival, and also let him bring a rich gift to thank and Honor Hou Shan Yu. In this way, Su Wu and Zhang Sheng and others rushed to the Xiongnu with more than a hundred soldiers and soldiers who had been temporarily recruited. The group gave Shan Yu both the Xiongnu envoys and gifts, which made Shan Yu's attitude more arrogant.
Just as Su Wu and the others were preparing to leave for China, the Xiongnu rebelled, and King Yan and Yu Chang plotted against them. Because Zhang Sheng supported Yu Chang, and Yu Chang was defeated, He Detained Su Wu and others in a fit of rage. Shan Yuben thought of inducing Su Wu to surrender to the Xiongnu, where would he agree, and he would not hesitate to commit suicide to save the name. Shan Yu admired Su Wu's integrity very much, and while looking for a doctor to treat his injuries, he continued to find ways to lure him down. However, Su Wu remained steadfast, and Hou Shan Yu imprisoned him in the cellar and did not give him food. Unexpectedly, Su Wu had been hungry for several days and had not died, and Hou Shan Yu thought to himself: Is he the reincarnation of a god? After that, Hou Shan Yu did not dare to embarrass him anymore and exiled him to the extremely cold north sea. Shan Yu also gave him a few sheep, saying that if he could make the rams give birth, he would let him go back to the Han Dynasty.
In the cold and frozen North Sea, it is difficult for plants to grow. After Su Wu arrived here, he could only dig up the fruits stored by wild rats and eat them. In such a difficult environment, he still found a way to survive. Soon, Marquis Shan Yu gave him a Xiongnu woman to paralyze Su Wu. Later, the woman bore him a son, and Su Wu named him Su Tongguo, and the family of three lived a life of male cultivator and female weaver in Beihai.
Five or six years later, Shan Yu's younger brother Yu Yu went hunting in the North Sea. Because Su Wu could weave nets for hunting and correct crossbows, King Yu valued him very much and provided him with food and clothing. After another three years, King Yu fell seriously ill and ordered someone to send horses, clothing, livestock and other items to Su Wu. After the death of King Yu, the Ding Ling people stole his cattle and sheep, causing his life to fall into trouble again. But he and his wife survived in the North Sea for 19 years, relying on their hands.
Although Shan Yu told the Han court that Su Wu had already died, the Han people did not believe it. The Han envoy inquired from many sides, and it took a lot of effort to meet Su Wu and bring him back to the Han Dynasty, which had been absent for a long time.