Truck driver Wong Ka Kui (Jackie Chan) went to the United States to congratulate Uncle Pao, who had immigrated to the United States, on his wedding. He learned that Uncle Pao planned to live a quiet life with his black wife after marriage, and that the supermarket he had run for many years had been sold to the young widow Elaine (Anita Mui). As he had a good impression of Elaine as soon as they met, Wong Ka Kui took the initiative to help Elaine manage the business. Soon, a group of punks led by Johnny began to maliciously disrupt and destroy the supermarket. Facing them, Wong Ka Kui bravely used his fists without fear, and at the same time did not forget to teach them the righteousness of life. However, before one wave was over, another wave arose. Wong Ka Kui was involved in the vortex of stolen diamonds and was hunted by the mafia.