University student Jiang Yu returns to his hometown to inherit the family business. Along the way, a storm leaves him stranded on a deserted island, where he unexpectedly rescues a mermaid named Xiyue and gains the supernatural ability to communicate with marine life. Meanwhile, his uncle Jiang Dahai takes advantage of his disappearance, conspires with relatives to seize the old family home and fish farm, and sells off all the family assets. Returning from the brink of despair, Jiang Yu relies on the help of marine creatures to catch extraordinarily valuable seafood and joins forces with the shrewd businesswoman Lin Wan. Together, they take on greedy relatives and powerful business rivals. Jiang Yu is determined to reclaim his parents' inheritance, expose the layers of conspiracy, and lead his fishing village toward sustainable seafood production and island tourism. In the end, he protects the blue ocean and finds both success and love, rising to become the King of the Deep-Sea Fisheries.