Returning to the 1980s, Gu Changhai and his younger sister are kicked out of their home, and even the fishing boat left behind by their father is seized. With nowhere else to turn, he rescues a crab with a broken claw and unexpectedly awakens the Sea Beast Contract System! The crab commands a whole army of crabs, sharks ride the waves, and all kinds of animals become his treasure-hunting helpers. While others head out to sea and leave their catches to chance, Gu Changhai returns with overflowing hauls every time! From struggling to put food on the table to buying boats and establishing a trading business, Gu Changhai protects his sister, stands up to his wicked relatives, and joins forces with a beautiful seafood buyer to turn their miserable lives into one that the entire village envies!