Jiang An, an aquatic farming water-quality management technician, manages Wang Laoliu's crayfish ponds. Wang deliberately undervalues the service, then shuts down aeration equipment without permission, depriving the juvenile crayfish of oxygen and falsely accusing Jiang An of causing the losses and demanding compensation. Honest farmer Uncle Li recognizes Jiang An's professional expertise and hires him to manage his own ponds. Wang Laoliu continues cutting corners, misusing equipment and feeding the crayfish low-quality feed. When disease breaks out in his ponds, he sells infected crayfish, illegally uses additives, deliberately damages other farmers' aquaculture facilities and introduces harmful chemicals into their ponds, ultimately breaking the law and facing criminal liability. Jiang An joins forces with trustworthy aquaculture farmers to establish a cooperative and promote scientific, standardized farming, achieving higher yields and incomes through expertise and integrity.