Aval Oru Thodar Kathai (1974)

Kavitha (Sujatha) is a working woman in a middle-class family. She works hard to support her widowed sister, unmarried sister, her blind younger brother, her mother, her drunkard brother Murthy (Jaiganesh) and his family. Her father abandons the family and becomes a saint. Her brother not only does not take responsibilities, but also creates additional problems for her. She has a longtime boyfriend of five years, Tilak (Vijayakumar) who wants to marry her, but she doesn't because of her commitment to her family. His eyes now wander to Kavitha's widowed younger sister Bharathi (Sripriya) who reciprocates his feelings. Kavitha, after reading her boyfriend's love letter to her sister, arranges for them to get married, thus giving up her chance of having a life with him. Meanwhile, Prasad (Kamalahasan) loves Bharathi, Kavitha's sister; but when he comes to know that she loves Tilak, he sacrifices his love for her and marries Kavitha's distressed friend, Chandra (Fatafat Jayalaxmi). Kavitha eventually accepts a marriage proposal of her boss (Gokulnath), when she realizes that her brother has become responsible enough to take care of her family. She decides to resign from the hard work, but could not as the result of a turning point in a typical Balachandar-style climax. Kavitha swaps her unmarried sister as the bride in her stead, as she is informed of Murthy's death minutes before. In the end she resumes her job and continues to support the family.