Chen Gang, a veteran machine repairman, works through the night to repair the production line, saving the factory tens of millions in losses. Yet the next day, he is heavily fined for violating factory regulations by drinking water on the workshop floor. Disheartened, he decides to strictly fulfill only his assigned duties and leave work on time without overstepping his responsibilities. Soon afterward, the imported production line, worth hundreds of millions, suffers a major breakdown that nobody in the factory can fix. The factory director comes to Chen Gang for help. Chen Gang repairs the equipment and uncovers a conspiracy involving an insider colluding with outsiders to sabotage the machinery for profit. In the end, the culprits are punished, the unreasonable factory rules are abolished, and Chen Gang's technical expertise earns recognition from headquarters.