Subramaniam Parthiban, an economics graduate from PSG College in Coimbatore, struggles to make ends meet. With five younger sisters to support, he takes on menial jobs to provide for his family. Captain Chidambaram, a retired army officer, Sivaji Ganesan owns a cycle shop in the same village and rents a portion of his house to Subramani. Chidambaram is a well-wisher of Subramani's family, and his eldest sister even works part-time at the cycle shop. Subramani's mother Janaki arranges for his eldest sister to marry a mute groom, citing the absence of dowry demands. However, Captain Chidambaram intervenes, advising the eldest daughter to wait for a more suitable match rather than settling for an unsatisfactory arrangement.
Subramani gets into a physical altercation with the manager, Vinayaga Moorthy during the personal interview, leading to a court case. Fortunately, Captain Chidambaram comes to his rescue, arguing on his behalf and securing his release. The family's poverty takes a toll on Subramani's fourth sister, who hesitates to inform her family about her puberty, fearing the additional financial burden. Meanwhile, Subramani's cousin, who harbors feelings for him, provides clandestine support. However, her family proposes that Subramani leave his family and live with them, a condition he refuses, ultimately leading to his cousin's marriage to someone else. Unbeknownst to his family with Captain Chidambaram's help, he embarks on a journey to Madras to seek employment opportunities. In Madras, he encounters a young woman who poses as a police officer and convinces him to stay nearby. However, she is later revealed to be the daughter of Chidambaram's friend.
Subramani first tries to break into the Tamil film industry as an actor but faces rejection. He then ventures into smuggling, only to meet with failure once again.
Once Subramani saves Chidambaram's friend's daughter from a group of miscreants, she eventually develops feelings for him. However, Subramani does not reciprocate her emotions. To maintain the illusion that Subramani has secured employment, Captain Chidambaram discreetly sends money to his family through money orders, with the help of postman Ponnusami R. Parthiban. Chidambaram suffers a heart attack but refuses surgery, opting instead to allocate the funds to support Subramani's family. Meanwhile, the struggling Subramani is found lying unconscious on the street but is rescued by Chidambaram's friend's daughter. She offers him work in the film industry as a junior artist for a daily wage of Rs.25. Captain Chidambaram suffers a second heart attack, prompting him to transfer his properties to Subramani's mother's name. He also makes arrangements to provide a monthly stipend to Subramani's family, making it appear as though the support is coming from Subramani himself. Also, he builds his own grave and expresses his unwavering faith in Subramani's future success.
At the film shoot, Subramani impresses director Bharathiraja Bharathiraja with his improvised dialogue, so he appoints Subramani as the film's hero and writer. Subramani's career as an actor takes off, and he achieves great success. On Bharathiraja's sister's advice, Subramani moves into Bharathiraja's house. Meanwhile, Captain Chidambaram, on his deathbed, requests that Subramani not be informed about his condition, asking his family to let Subramani focus on his career. After the film's success, Subramani arranges marriages for his three sisters. He also accepts the love of Chidambaram's friend's daughter. However, during the wedding ceremony, Subramani discovers that his sisters are not interested in marrying the groom Subramani had chosen as they were motivated by money.
Subramani then realizes that his sisters are actually in love with three other men: a tailor, a laundry man, and Postman Ponnusami. These men had helped Subramani during his struggling days and were willing to marry his sisters without demanding any dowry. Subramani wholeheartedly accepts the three men as his brothers-in-law and agrees to their marriages.
