Mobsters are smuggling guns into Hong Kong. The police orchestrate a raid at a teahouse where an ace detective loses his partner. Meanwhile, the two main gun smugglers are having a war over territory, and a young new gun is enlisted to wipe out informants and overcome barriers to growth. The detective, acting from inside sources, gets closer to the ring leaders and eventually must work with the inside man directly.

Centers on Captain Manfred who is caught in the line of fire between high levels of corruption and malice. He must solve a brutal murder to prove his partner's innocence and unearth the truth behind Hong Kong's police force. The investigation brings him to an unlikely collaboration with sly, man-of-the-world Inspector Kee from the Narcotics Bureau, whose motives are not what they seem.

Weedy office worker Cheung is sent to a remote village to secure property rights for his real estate company. Two martial artists run the village's teahouse, which was once the kung-fu school of their teacher Master Law. Law is in fact lying unconscious upstairs in a three decades-long coma, but he awakes when gym boss and local landlord Pong attempts to secure the teahouse for redevelopment. Law mistakes Cheung for a former student and starts training him in preparation for a martial-arts tournament at Pong's gym that will decide all their fates.

A dying teacher instructs his final student to check on the activities of five former pupils, each of whom he taught a unique and special style of kung-fu to: The Centipede, Snake, Scorpion, Lizard, and Toad (hence the title). His final student, who knows a little of each style must team up with one of the other good students to destroy the evil ones if there are any. Greed and treachery ensue as the student discovers that some of the students are indeed evil. But which one can he trust enough to team up with?