Sathyam movie based on the story of Sanjeev Kumar (Prithviraj) who is the son of head constable Ayyappan Nair (Thilakan) who is a sincere policeman and who was accused of accepting bribes and dismissed from service by his senior officer Mukunda Menon (Ananda Raj). Menon is now the city police commissioner who is determined to create problems for the Nair family and ensure that Sanjeev is not selected to the police academy. Ayyappan Nair longs to see his son become a policeman. Sanjeev on the other hand works very hard to fulfill the dream of his father. However, he soon realises that he can never become a police as long as Menon is alive. He beats up Menon and locks him inside an old mansion and forces him to write a letter to his office that he is going on a pilgrimage for his bad deeds.
A sincere officer (Lalu Alex) takes charge and help Sanjeev achieve his goal of becoming a sub-inspector. Sanjeev turns out to be a very daring cop who cleans up the city within his limitations and the tacit support of the chief minister (Venu Nagavally). Meanwhile, Menon escapes from captivity and decides to take revenge on Sanjeev. Will Menon succeed in his aim? What does life have in store for Sanjeev? These are the few answers that you discover in the climax.