A police informant sent a letter containing sensitive information on an illegal drug operation to his friend, Yi-Ching. While on vacation in Thailand, the informant is assassinated by the drug lord's henchmen and, to cover-up their operation, they attempt to eliminate Yi-Ching and double-agent Lau. Back in Hong Kong, police detectives Muscles and Ricky Fung are assigned to protect Lau and Inspector Barbara Woo is assigned to protect Yi-Ching. She takes her to the hideout of the "Five Lucky Stars" and also enlists their help in bringing down the drug operation. Written by Oliver Chu

Yu Chau is a cop who has gone so deep undercover within the triad. He can no longer tell which side of the law he's on. When he accidentally kills one of his pals in an operation, he runs off into the boonies to lick his wounds. Upon his return, he teams up with fellow officers Jim and Jackie to catch a triad Boss, only to unveil collusion with government officials at the highest level. Yu Chau once again faces the dilemma of taking the law into his own hands...

The Hong Kong Police placed 1000 undercover officers in the various Triad groups in their efforts to bring down the criminal organization in Hong Kong. After one undercover officer's identity is discovered and he is killed, the pressure is put on one gang, suspicious of each other and everyone around them. Betrayal, deceit and murder bring this group of 'brothers' into a collision with the law, and each other.