A large truck traveling on a national highway at night suddenly explodes with a thunderous sound. A charred passport with the name Wang Yinghan written on it is found at the scene of the accident. Wang is the biggest drug lord in the postwar era, and the special investigation team is investigating his background. The special investigation team assumes that a traitor has killed Wang, and they quickly move into action. A few days later, a man named Chen arrives in Japan from Hong Kong.