Kabali (Sathyaraj), an orphan, lives in a slum with an old Brahmin woman named Pangajam (Manorama) and he considers her like his mother. Kabali is a fisherman and also the slum's rowdy but he has a heart of gold. He has gone in jail many times only because he fought against injustice.
Suganthi (Bhanupriya), a chorus singer, often returns home late and she is an orphan. For her safety, she uses Kabali's name to avoid the rowdies and she lies that she is his girlfriend. One day, Kabali meets her and slaps her for misusing his name. Thereafter, he falls in love with her.
Sundar (Sarath Kumar), a rich man, is a womaniser and is able to have any girls he wants by money or by force. His mother (Sathyapriya) sympathizes with Suganthi and decides to get her married to Sundar.
When Kabali decides to propose his love to Suganthi, she first tells to him that she accepted to get married to Sundar and she invites him for the wedding. Kabali knows Sundar's bad habits but he doesn't want to hurt her.
At the wedding day, Sundar stops the marriage because he suspects the relationship between Suganthi and Kabali. In anger, Kabali challenges him to arrange their marriage another day. What transpires later forms the crux of the story.