Nandha Gopalan Kumaran is a social worker and do-gooder, specialized in organic farming. He has a huge support from the youngsters in his village who were inspired by him quitting his high-profile job for serving his country. He lives with his mother Viji; father Ramanan, a former military officer; and a possessive wife, Geetha Kumari, who is a major strength for him.

Kumaran happens to meet an old friend, Raja, the right hand man of the area MLA, while trying to solve the problem of a few youngsters. He gets a big shock upon finding that what he tried for a long time and failed was done by his friend through the area councillor in a single phone call. Meanwhile, a few shopkeepers, middlemen, and others who alarmed by Kumaran's organic farming give him an ultimatum and later attack the people and burn their farms using chemicals when he refuses to give up. In order to make things good, Aruna Giri, a native, asks Kumaran to meet the MLA, Pandiyan, who happens to be a ruthless narcissist. He agrees to help if Kumaran joins his political party, KMK, along with 500 others from his villages, to which he is forced to comply. Pandiyan ill-treats Kumaran and asks him to clean his toilet, buy biriyani, and even bring a sex worker. Though furious at first, he decides to use the situation to gain Pandiyan's trust and in the process do good for his village. He discovers that Raja is suffering from terminal cancer and will not live long.

Kumaran happens to meet Vanathi Thiagarajan, who was appointed by the party with a monthly income of 2 crore to help them win the upcoming elections. Impressed by Kumaran, she seeks his opinion soon starting an affair with him, much to his wife's suspicion. Kumaran asks Vanathi to select Kesavamoorthy, the Home Minister, as their target. Despite threats from Killivazhavan "Killi", the Chief Minister, he manages to expose the ill deeds of Kesavamoorthy and arrange a scripted revolt for their party's benefit. However, Raja makes Kumaran kill him so as to intensify the people's emotions for their party and make the latter an important figure. Kumaran is arrested and later admitted in the hospital. Killi is shocked to find that Kumaran has turned the tides against him and decides to kill him. Kumaran is soon confronted by goons in doctors' disguise, whom he single-handedly defeats with great difficulty. The next day, he puts up a show in the front of his villagers, gaining their trust. Pichai Muthu "Pichai", the leader of KMK, is alarmed by the popularity of Kumaran and also finds that Vanathi is helping him. He decides to nominate Kumaran as the candidate for the upcoming elections to the legislative assembly.

As his character became negative after being ill-treated by Pandiyan, Kumaran makes a plot to kill his own family to become the chief minister. The night when he is to address his villagers, as per his plan, goons arranged by him attacked them, and his wife is stabbed, but the goons could not kill her because Vanathi came to her rescue. However, the goons successfully kill his parents according to his plan. An angry Kumaran addresses the gathering with pretending to be with full vigour, causing them to attack and kill Pichai and his accomplices while a bomb already set by Kumaran inside an audio system of the caravan blasts. Vanathi decides to leave their relationship to Kumaran. Kumaran forms a new party, Makkal Munnetra Kazhakam, and wins the upcoming elections forming a coalition government. He reunites with his wife. Kumaran becomes the new chief minister and while in a channel interview mentions about strengthening his hold in the state.