Senapathi`s sons have always desired the power and success their father has enjoyed. So, when a coveted spot in the family business - that of city`s most influential gangster - is up for grabs, the three brothers are lured into a collision course. Blood ties will unravel as a bloody battle for power begins.
Thangarathnam is a film, which is based in a village. The hero, a tempo driver carries vegetables from the nearby village to the Ottanchathram Gandhi market where the fundamental rule is that whoever gets the vegetables first, gets the best price. This leads to constant clash between the hero and another tempo driver. How the rivalry between the two affects the love life of the hero and how he comes out of the situation forms the crux.
Suriya is a spoiled brat who deceives girls in the name of romance. Kousalya is one of the victim who falls into his trap. One day, Suriya gets kidnapped and finds himself trapped in a wooden box akin to a coffin. Following Suriya's parents complaint, ACP Devendra Kumar (Rahman) takes up the case. What happens in course of investigation forms the rest of the story.
Vikram Prabhu is a BSF staff posted at the India-Pakistan border. He falls in love with Ranya Rao, a girl from the nearby village. After a chain of events, he gets caught to the Pakistani army torture camp to render demoniac torture and subsequently kill the Indian security staff crossing the border, accidentally or intentionally. The rest deals with what happens to Vikram Prabhu and his love.
A sister in law (Akshaya) falls in love with her brother in law Akhilan (Arya). But he refuses her because he adores his wife (Renuka Menon) and he never would cheat on her. He hides all facts to his wife in order to protect her. Finally the sister in law commits suicide after a tragedy that becomes the climax of the film.