Lu Qing worked with his cousin and cousin's wife to catch softshell turtles for three years, helping them build their fortune with his family's traditional skills of reading the water and making turtle-attracting mud. Now that they have made enough money, the couple steals his rudimentary formula and kicks him out, giving him only fifty copper coins before driving him off their boat. With his mother seriously ill and in urgent need of money to buy ginseng, Lu Qing has no choice but to purchase an old bamboo raft and a fish basket and venture into the perilous Blackwater Dragon Pool. His true ancestral secret recipe contains ash made from bitter snake grass, which repels venomous snakes and attracts only century-old softshell turtles with golden-edged shells. The bait stolen by his cousin's wife is merely an unfinished version. As night falls, Lu Qing bravely enters the Dragon Pool on his bamboo raft, while his greedy cousin and cousin's wife cast their nets using bloody bait, unaware that they have already attracted venomous river snakes.