Aquatic village crab farmers look forward to the National Day market price rise. Lu Ming combines market information to judge the risk, chooses to sell his own Chinese mitten crabs in time, and brings his parents to live in the city. The villagers do not understand and mock him, still insisting on hoarding goods waiting for high prices. Holiday market changes, hoarders encounter operational difficulties, and Lu Ming's family guards peace due to rational choice. Facing doorstep entanglements, Lu Ming uses facts and rules to protect his family, rejects unreasonable demands, and finally returns to a peaceful life. The story shows the importance of rational judgment and family guarding.