The film tells that in ancient times, the emperor Ming sent Dongchang Supervisor Gao Dehai to lead a fleet to the East China Sea to seek the fountain of youth. Unexpectedly, he was attacked by a dragon on the way, sunk the ship accidentally, and the fleet strayed into the deserted island to take an adventure. Jin Yiwei's guard Yan Lie came across "the last shark man in the world"—the beautiful and kind Xiyin, and the story of his love with Xiyin

Years ago the mermaid Xi Yin saved the Imperial guard Yan Lie. They fell in love, but the mermaid returned the ocean. It was rumored that the mermaid has a magical treasure, and Imperial concubine Shen Mei wants to claim this, at any cost.