The story is set in the year 2035, when Chinese scientist A Tai successfully achieves communication between humans and fish using the TAIHU3.0 Photon Absorption System (Photon Absorption Robots), earning him the Nobel Prize in Biology and shocking the world. Rewinding time, A Tai’s grandfather had encountered the legendary Fish King in his youth—a story that was always his grandfather’s pride but also the reason he was mocked by the villagers. Driven by curiosity and a desire to prove his grandfather was not lying, A Tai sets out on a fishing boat to search for the Fish King. His classmate Cui Bo, pursuing her own dreams, secretly follows him aboard. The two children hang A Tai’s grandmother’s pendant high up to attract the Fish King, who is said to love shiny objects. The enormous and beautiful Fish King arrives as expected, appearing in the depths of Lake Taihu at night. Later, through the Fish King, A Tai and Cui Bo discover the secluded White Turtle Island and befriend its villagers, who have lived in seclusion for a thousand years, embarking on a series of magical adventures.