velan (m.g.r) is an innocent village guy whose livelihood is rearing cattle and looks god in them. nagalingham (s.a.ashokan) municipal chairman is a crooked & cruel person, performs a lot of atrocities in the town also involved in anti-social and illegal activities. he has an arrogant daughter kamala (lakshmi) and a good-nurtured son sundharam (cho ramaswamy). sundaram always teases and revolts against his father for his evil deeds. once velan's cows obstruct kamala's way, she beats the cattle when velan becomes furious and beats her in turn. but gets frightened when he comes to know that kamala is chairman's daughter. nagalingham sends his men to kill velan but sundharam rescues him and changes his attire as a college student. parallelly, advocate r. k. sathiyanadhan (v. k. ramasamy) an honest person who always supports the justice, backs the piety and gives a tough fight to nagalingham. he leads a happy family life with his ideal wife annapurna (s. varalakshmi) and a daughter radha (jayalalitha). sathiyanadhan fixes his daughter marriage with his childhood friend sripathi's son raghu (again m.g.r) who looks alike velan. on the advice of sundaram velan reaches sathiyanadhan's house, they mistake him as raghu and highly honors him. here velan & radha fall in love with radha. eventually, raghu arrives to apprentice sathiyanadhan, he was caught by goons of nagalingham they take him to nagalingham's house and beats him. however, raghu escapes, enters sathiyanadhan's house where he is surprised to see velan, explains raghu about his problem and he understands the fact. knowing that velan is in love with radha he stops and asks him to stay along with him. now they play a confuse drama without revealing their identity. meanwhile, raghu meets kamala, she again teases him mistaking him as velan but afterward feels sorry when both of them fall in love. on the other hand, sundharam loves their maidservant kaveri (sachu). unfortunately, once radha witnesses raghu & kamala, misunderstands velan when raghu turn up affirms the entire story. hearing it, sathiyanadhan throws velan out and decides to make radha's marriage with raghu. but raghu refuses it and says he is going to marry kamala. then narasimha declares nagalingham as his father's murderer who projected it as a suicide. listening to it raghu breakdowns and he also comes to know his father gathered pieces of evidence against nagalingham in a dairy and secured it in a secret place. in that anger, raghu burst out on nagalingham, knowing that raghu is sripati's son he captivates him and blackmails sathiyanadhan for the dairy. immediately, sathiyanadhan rushes to nagalingham's house when nagalingham is about to kill sathiyanadhan velan comes to his protection where he plays a drama as if he has murdered sathiyanadhan. at this moment, everyone understands velan's virtue, simultaneously, raghu is shifted to nagalingham's den. ultimately, velan breaks out dairy's secret, finds the route map to nagalingham's den, sees the end of him and protects raghu. finally, the movie ends on a happy note with the marriages of velan & radha, raghu & kamala, and sundharam & kaveri.