Gu Ou is set up by his ex-girlfriend Wang Yali and Liu Tianci and left stranded on a deserted island. Unexpectedly, he awakens the Sea God System, gaining the abilities to sense seafood and breathe underwater. After escaping and returning to shore, he catches prized butter crabs and meets Gao Qingyuan, the owner of a seafood restaurant. Liu Tianci monopolizes the seafood supply to force Gao Qingyuan into submission, but Gu Ou comes to the restaurant's rescue with 200 jin of silver pomfret. When ship king Zhou Weitian attends a banquet, Liu Tianci shows off an emperor crab to steal the spotlight. Gu Ou makes a grand entrance with a wild large yellow croaker. He later discovers red abalone, bluefin tuna, and ambergris, making a name for himself. During an underwater treasure hunt, Gu Ou encounters Liu Tianci again and brings him to justice. In the end, Gu Ou and Gao Qingyuan become a couple.