Muthu, the son of a poor villager, was faulted by his school teacher for not disclosing the name of the boy who stole a watch from a nearby watchshop. Later when Muthu reported the theft to the police, he was framed by the head-constable, whose son was the real thief, and convicted. Educated in the reformatory school, Muthu learns the tricks of the criminal trade and their modus operandi. When he comes out of jail, by chance, Muthu gets the certificates of a man with a similar name and joins the police force, with false credentials. When Muthu's superior officer threw out his daughter for having an affair with the son of a known criminal, Muthu marries her. Using his knowledge gained while in prison. Muthu becomes a sort of private detective, who traces and restores stolen property to the true owners. This results in Muthu being convicted a number of times and he ends up serving a long stretch due to a murder case.