Thalapathi is a 1991 Indian Tamil language film directed by Mani Ratnam.Surya (Rajinikanth), the abandoned child of an 14 year old unwed mother Kalyani (Srividya), is brought up by a generous lady living in slums. He grows into a fearless kind-hearted ardent fighter to fight the injustice that takes place in the town. These qualities lead him to cross swords with the local don Devarajan (Mammooty). Devarajan's friend is beaten up terminally by Surya, and Deva threatens Surya saying that your life will soon end up in danger if my friend was laid to rest.
Then soon as his friend passes away, Surya then gets placed in prison. However, when Deva discovers Ramana's offense, he decides to get Surya released from jail. Surya himself is surprised to see Deva get him out from jail, and there he tells him nyayamnu onnu irrukku (there is such a thing as justice). And from that glorious moment, Deva surrenders his ego and offers his hand of friendship. Surya too declares that he would be Deva's best friend till death. Deva makes Surya his commander "Thalapathi". Both of them rule the town not only with their muscle but also with their sense of justice.
But in the eyes of the Government, they are considered as antisocial elements. Arjun (Arvind Swamy), posted as the new District Collector, plans to arrest both Deva and Surya, so that he could put an end to their brutal activities. But his opportunities all goes in vain. In the ensuing struggle between the Collector and Deva/Surya, Surya learns that Arjun's mother, is his mother too. Surya promises his mother that he will not harm Arjun but refuses to leave Deva, whose friendship is more valuable to him than his relationship with his brother. Deva is stunned to learn that Collector and Surya are brothers and admires Surya for not parting with him in spite of discovering his identity. During the process of surrendering to the Collector, assuring him completely stopping their activities, Deva is shot. Surya, in a fit of rage, kills the person who was the cause for Deva's death and surrenders to the Police after performing the final rites of his close associate. The Collector goes to another place on a new posting accompanied by his wife. The mother then changes her mind to stay with her elder son, Surya.