N. Pugazhendi "Pugazh" is a news reporter in Chennai. One day, a riot between students and bus drivers erupts in the city, and the Chief Minister Aranganathar, Raghuvaran, tells the police not to arrest the protesters because they belong to his community and political party, a conversation Pugazh records on video.
Pugazh also meets Thenmozhi, Manisha Koirala, and is drawn to her honesty and bravery, but her father, Vijayakumar, does not approve of his daughter marrying someone who isn’t a government employee.
Some days later, Pugazh interviews the Chief Minister on television and confronts him about actions by his party and his inaction during the riot. Aranganathar insists that Pugazh does not understand the pressures a Chief Minister faces, and he challenges him to act in the post for a day, which Pugazh accepts.
In his allotted 24 hours, Pugazh takes steps to curb corruption and boost welfare in Tamil Nadu, aided by an honest government secretary, Mayakrishnan, [Manivannan]. Pugazh’s final move of the day is to press corruption charges against the ruling party; Aranganathar is arrested but bailed out by the attorney general. After his release, Aranganathar sends goons to kill Pugazh, but he escapes with only minor injuries.
Pugazh visits Pooncholai and is warmly greeted by the villagers before spending a peaceful day with Thenmozhi. Meanwhile, Aranganathar’s public image is damaged, the coalition parties withdraw their support, the legislature is dissolved, and a general election looms. Voters rally behind Pugazh, who initially hesitates to become Chief Minister in order to maintain a normal life. Mayakrishnan eventually persuades him to sacrifice his comfort, run for election, and he wins a sweeping majority, securing all legislative seats.
As Chief Minister, Pugazh works to develop the state and raise welfare standards, even as Aranganathar and other politicians lash out in anger and hire a hitman to kill him. Pugazh slips away to visit Thenmozhi and nearly gets caught by the would‑be assassin. Thenmozhi’s father presses Pugazh to choose between the Chief Minister post and a life with his daughter, while Pugazh’s parents agree to speak with Thenmozhi’s father to try to sway him.
Mayakrishnan phones to warn that a bomb has been planted in Pugazh’s home, and the blast kills Pugazh’s parents just as the day unfolds. Pugazh confronts Aranganathar and learns of a broader plan to plant bombs across Chennai. Pugazh and Mayakrishnan alert a bomb squad, which manages to defuse all but one of the devices.
Aranganathar blames Pugazh for the chaos, calling it a tactic to win public favor. Pugazh invites the Chief Minister to his office, and in a tense moment, Pugazh shoots himself but is not seriously harmed, then hands the gun to Aranganathar. Security guards arrive to find Aranganathar aiming at Pugazh, and they kill Aranganathar in the ensuing confrontation, with him recalling the interview that started it all.
Pugazh is left conflicted—pleased to continue reforming the state but troubled by his role in Aranganathar’s death and the political games he felt compelled to play. Mayakrishnan reassures him that his work was for a worthy cause and that Aranganathar deserved his fate. With Thenmozhi’s father’s blessing, the couple’s engagement is reaffirmed, and Pugazh’s governance brings development and a climate free from the worst violence and corruption that once plagued Tamil Nadu.
