Why did the legend of chasing fish make Jin Mudan immortal?

Jin Mudan, the legend of chasing fish, is famous for Guanyin. In The Legend of Chasing Fish, Jin Mudan died and was touched by Guanyin. Conscience found that she released the essence of the cat demon, found that she was the lucky dragon lady of Guanyin, and went back to accompany Guanyin. The Legend of Chasing Fish is a 3D mermaid myth costume magic drama jointly produced by CCTV, Zhejiang Guangsha Culture Media Group Co., Ltd. and Dongyang Futian Film and Television Co., Ltd., directed by Zhao and Xiao, played by Dai Jiaoqian and co-starred by Cao Xinyue, Baishan, Li Zixiong and Zhang Mingming. At the beginning of the first episode, 18-year-old handsome Zhang zhen plays the flute at the seaside. The beautiful flute attracted HongLing in the sea. HongLing is full of curiosity about human affairs. Listening to the wonderful flute, she took it into Zhang zhen's hand by magic and held it in her hand. HongLing wanted to know how humans played the flute, but the flute was very ugly.