Fisherwoman Li Qingyue and her younger sister go out to sea to catch fish. When they encounter a giant snake attack, they fish out a mysterious wooden box containing an injured little sea otter that can speak. Li Qingyue takes it home out of a soft spot in her heart, and her son Xiaoche names it Mengmeng. After a night, the sea otter transforms into a three-year-old girl, and Li Qingyue decides to adopt her. Mengmeng can communicate with marine life, guiding Li Qingyue to catch precious seafood and improve her family's financial situation. The bully Ma Shangfei covets the seafood, repeatedly plotting to seize it and block their sales channels. With the help of Lin Lei, Li Qingyue braves the perilous "Ghost Sees Sorrow" sea area and sells her seafood at a high price. During the sea area bidding, Li Qingyue wins the abandoned reef area at a low price and finds a large number of top-grade abalones with Mengmeng's help.