The gangster "Hua Gu Long" (played by Nick Cheung) and his mother (played by Roland) depend on each other for survival. Due to a car crash, Hua Gu Long was detained by the old policeman "Qian Chong" (played by Danny Lee). Fortunately, the mother of the dragon used her skills of pretending to be stupid to help him escape. Hua Gu Long and his son, who owed usury everywhere, had to often act to avoid debt collection. On this day, the mother of the dragon won the horse race, and Hua Gu Long, who was collecting profits, encountered the creditor being killed by his enemy. Hua Gu Long accidentally discovered where the creditor hid the money and escaped by chance. He was given "protection" all day by the millennium bug as an important recruit for the murder case. Hua Gu Long, who had only seen the murderer's butt, thought about escaping and stole the hidden gold at the crime scene. However, the daughter of the millennium bug was pure and lovely, so he couldn't bear to leave. On the other hand, the murderer found Hua Gu Long and his son according to the information released by the millennium bug, which led to the dragon and the bug joining hands to fight against the murderer.