A secret agent sets out to stop an evil scientist who is about to unleash on the world a virulent biological strain he has developed during experiments on rats.

An ex-cop goes rogue and sets out to hunt down a ruthless drug cartel, even though it goes against his professional conduct. Meanwhile, the beautiful daughter of the ringleader who was killed in an internal feud has returned to Thailand from Hong Kong to take revenge on her father. She teamed up with the ex-cop to pursue the crafty villain of the local opium trade, while an anti-narcotic detective sent by the government also joins the fray.