The film begins by showing Rajni as Balu, a lavish spendthrift with a cavalier attitude towards life. Born to a rich father Chandrasekhar (played by VS Raghavan), Rajni has a rampant and aggressive behaviour and gets into confrontations wherever he perceives injustice. Worried about Rajni's behaviour, his father decides to send him to his friend and ex-militaryman Gangadharan's (played by Sendhamarai) village, to work for him for one year with a condition that Rajni will not reveal that he is the son of Chandrasekhar. Rajni slowly gets accustomed to the village life and learns to work hard and develops a good relation with Gangadharan and his family. During his stay, he spars with an arrogant rich girl, Sumathi (Madhavi). Madhavi assuming Rajni to be a poor villager tries to humiliate him and Rajni responds in kind. Eventually they both fall in love. In a triangular story line, Gangadharan's daughter played by Sulokshana, also falls in love with Rajni, but learns he is in love with Madhavi. A dejected Sulokshana agrees to marry a man (Sathyaraj) chosen by her father. Madhavi's father (played by Vinu Chakravarthi) who had agreed to get her married to his partner's son rescinds the proposal on Madhavi's request. This enrages the villainous partner (Srikanth) and he kidnaps Madhavi to marry her by force to his son Nizhalgal Ravi. Rajni rescues her and leaves her in the custody of Satyaraj and Sulakshana. However Sathyaraj betrays his trust and turns her over back to Srikanth and Nizhalgal Ravi. In a final fight sequence, Rajni rescues Madhavi and returns her to her father. Rajni then leaves the village after learning hard work, discipline and many other good virtues from Gangadharan. The final scene shows Madhavi and her father at Rajni's father house discussing marriage for Madhavi. Madhavi refuses but soon realizes that she is actually in Rajni's house and to everyone's surprise Rajni clad in a full suit walks down the stairs when the credits start rolling.

• Rajinikanth as Balu
• Madhavi
• Sulakshana
• Senthamarai
• V. S. Raghavan as Rajini's father
• Vinu Chakravarthy
• Srikanth
• Nizhalgal Ravi
• Nassar
• Janagaraj
• Master Vimal
• Ennatha Kannaiya
• Vani
• Kovai Sarala
• Sathyaraj
• T.K.S. Natarajan
• Omakuchi Narasimhan

The soundtrack was composed by Ilaiyaraaja. The song "Kadhalin Deepam Ondru" is based on the Charukesi raga and became one of the most popular songs from the film.^[6] Ilaiyaraaja was supposed to sing this song but was unable to do so due to hernia operation; Raja then recorded in a tape recorder by whistling and sent it to S. P. Balasubrahmanyam.^[7] The song "Aasaikliye" is based on Arabhi raga.^[8] In May 2015, the FM radio station, Radio City, commemorated Ilaiyaraaja's 72nd birthday by broadcasting the composer's songs in a special show titled Raja Rajathan for 91 days. "Kadhalin Deepam Ondru" was one of the most requested songs on the show. Actor Karthik remarked, "It’s my all-time favourite. A solo number, it’s about love, the most beautiful emotion. Dancing to a song is all right, but relishing a song and singing along... it’s beautiful."^[9]

All lyrics written by Panchu Arunachalam; all music composed by Ilaiyaraaja.