Muthazhagu(Sarathkumar) is a youth leader in his own father Aalavandhaan's(Nasser) political party but his honest principles make him a thorn in the side of his father. Aalavandaan, together with his two sons-in-law, has accumulated wealth and power through politics and is now aiming for the Chief Minister's chair. When things come to a head, Muthazhagu walks out of the party and contests as in independent candidate from his father's constituency.

In order to project the hero as a man who cleanses the system, movies in this genre have to first show us how dirty the system initially is. So Nam Naadu starts off showing us the current state of politics and that always makes for interesting viewing. The film doesn't break any new ground or venture into really biting satire (who knows who Sarathkumar would need in the future. So he can't really antagonize anybody, I guess!) but Nasser's performance as the corrupt minister and Ramesh Khanna's comments(though sometimes they seem too many) help present a somewhat damning view of politics.

Having a honest politician go up against a corrupt politician is not really new. But the film manages to change the dynamics a little bit by making the two son and father. While we usually see fathers wanting their sons to become better men, here's a father who wants his son to go the other way! He sees his sons-in-law as his real sons while the good son is the black sheep. Nasser's frustration with Sarath's good deeds and his anger at his wife, who he sees as siding with his son, lead to some funny moments.

In Tamil cinema, we are used to heroes being overtly heroic and action-oriented. Brain alone will never do and brawn always speaks louder. And these are even more important when you have a title like 'Supreme Star'. So Sarathkumar acts like a politician, passing orders and overseeing the police force for a while. The movie holds some interest during these portions. But once Sarath shrugs off the politician's clothes and dons his usual action-hero clothes, the film loses all semblance of realism. So we are subjected to scenes like the Home Minister, who has the entire police force waiting for his orders, donning a tracksuit and singlehandedly fighting with rowdies who are after Karthika. This extends right upto the over-the-top climax but only after unnecessary sentiments enter the picture too.

Sarath looks the part of the politician though it does rankle a bit when he refers to himself as 'one of the youngsters in whose hands the future of the country lies'. Karthika fits the role when playing the shy, timid girl. But once we're used to that, the glamorous dresses and fast dance moves don't sit too well on her in the song sequences. Nasser enjoys himself as the corrupt minister. He looks like the only actor who understands the campy nature of the film and so revels in it. Saranraj is the usual villain while Abitha, in a rather big demotion from the heroine role in Sethu , plays his wife.