Thangaikku Oru Thalattu (English: A Lullaby To Sister) is a 1990 Tamil language drama film directed by K. S. Madhangan. The film features Arjun Sarja and Seetha in lead roles. The film, produced by P. Ramakrishnan, had musical score by Sankar Ganesh and was released on 23 November 1990.
Gopi (Arjun Sarja), a poor youth, lives with his mother (K. R. Vijaya) and his uncle Baba.
J. M. J (Ramesh Raja) is a businessman who cheated and killed rich persons. Arun (Delhi Ganesh), an honest journalist, is killed by J. M. J's henchmen. Prakash, who looks like Gopi, arrests, an innocent young woman, Priya (Seetha). Janaki, Prakash's sister, is Priya's friend. Prakash believed that Priya was a prostitute but in a function, he knows her real identity and he apologizes to Priya.
Priya becomes a journalist like her brother. With Arun's written and photos evidence, she investigates on J. M. J with Prakash's help.
Janaki gets married and she dies with her husband in a car accident. Prakash arrests his sister's killer but due to the finance minister's kidnapping, he have to release him. Later, he saves the finance minister without releasing his sister's killer.
Gopi's uncle reveals to Gopi the truth. Gopi had a twin brother and his father was killed by J. M. J. Gopi is kidnapped by J. M. J to spoil Prakash's police career. He manages to escape from there. Gopi's uncle also reveals to Prakash his past.
Gopi and Prakash fight against J. M. J's henchmen. Gopi dies with J. M. J.
Arjun Sarja as Gopi / Prakash
Seetha as Priya
K. R. Vijaya as Gopi's mother
Ramesh Raja as J. M. J
Renuka as Kasthuri (Stella)
Senthil as Arumugam
Delhi Ganesh as Arun (guest appearance)
The film score and the soundtrack were composed by film composer Sankar Ganesh. The soundtrack, released in 1990, features 5 tracks with lyrics written by Muthulingam and Shanmugham.