Illegal development by the Wang Group causes the tidal flats to collapse, trapping workers. Jiang Yu, a hidden martial arts master, arrives with his otter and walks across the mud to rescue them, saving three workers amid towering waves. Boss Zhao and the wealthy Gu Yanqiu are punished according to the law for damaging the ecosystem and coveting the King Crab. Jiang Yu releases the century-old King Crab back into the sea to protect the coastal waters and passes on the art of walking across mud, upholding the ideal of harmonious coexistence between humanity and nature.