This film is about ancient aristocrats who stored their treasures underwater, which can be inherited by future generations with the right credentials. The deposit and withdrawal of treasures are both completed underwater, which can be simply understood as an underwater bank. For generations, the underwater bank has been controlled by three prestigious families who still operate this business today. However, 20 years ago, during a routine "golden soup" operation, a huge tentacle suddenly appeared in the lake, almost wiping out the three skilled members of the families present, leaving only a young boy named Yi Sa as the sole survivor. 20 years later, Yi Sa, now the leader of the Yi family's underwater creatures, experiences physical anomalies and, in an effort to uncover the truth about the disaster from 20 years ago and to save himself, teams up with Ding Yu Die, a member of the Ding family's underwater creatures, and Zong Hang, who stumbled upon them carrying the ancestral plaque of the Jiang family, to once again dive into the lake for another "golden soup" operation....