advertising company staff mo tak-fai (lau) and his friend lai chi (chan) go to mainland china for a business trip. chi smuggles some relics, leading to them being chased by the police. they go into a cave to escape capture, but chi is bitten by a poisonous snake. he finds a medicine belonging to an ancient hero named long jianfei and shares it with tak-fai. not only does the medicine detoxifies chi, it also bestows tak-fai and chi internal strengths. they also rescue princess yunluo (wong) and her maid xiao man (mui) from the yuan dynasty after 800 years of slumber but in the process also releasing a two-hundred-year-old evil martial arts expert tian can (yuen).