A police informant sent a letter with important information on an illegal drug operation to his friend, Yi-Ching. While in Thailand, the informant is killed by the drug dealer's henchmen and, to continue their business, they try to murder Yi-Ching and double-agent Lau. Back in Hong Kong, police detectives Muscles and Ricky Fung's duty is to protect Lau and Inspector Barbara Woo protects Yi-Ching. She takes her to the "Five Lucky Stars"'s place and help knock down the drug operation.