Saravanan(Sarathkumar) works as the bus driver for a ladies college and Nikitha, one of the college students, has fallen for him. When four goondas belonging to a caste-based political party get off easy after causing the death of a young woman, Saravanan takes justice into his own hands and kills them. Eventually we learn of his past as Chatrapathi, a decorated major in the army and the reason behind his enmity with Chakravarthy(Mahadevan), the leader of the same political party.

Chatrapathi almost equals Madurey in the ridiculousness of its basic setup. We are expected to believe that an army officer who has won the highest possible award for an armyman, who has been on the cover of all major Tamil magazines and has earned the respect of the President and the Prime Minister, is leading a life of complete anonymity as a bus driver in Madras! But the movie maintains Sarathkumar's respect by making him the strong and silent type and also making the dances, duets, etc., the product of Nikitha's imagination. There are a couple of strong dialogs(like Sarathkumar's mention of Mother Teresa's opinion about wasting and his reasoning for why saving up does not make a lot of sense) that add to his character's respectability.

Expectedly, Chatrapathi contains quite a bit of action. But the action is so completely over the top that it simply serves to undo some of the positive things the movie has going for it. For instance, the scene where the foursome are brought to Sarathkumar is picturised well. But the subsequent fight is so full of flying and leaping stunts that it destroys the seriousness the movie had managed to build until then. The same is the case of the military mission Sarathkumar takes on in the flashback. Just when we are starting to think that the sequence has been picturised well, he turns into a one-man army performing unbelievable stunts, which pushes the movie right back into the masala realm.

Vadivelu has a separate comedy track which mostly consists of him earning the public's ire after selling some dubious products. Some of the sequences, like the revelation of the modern machine for killing bedbugs, earn some chuckles. But the credit for most laughs in the movie goes to Ilavarasu and his constable/buddy. As the DC who listens to the politicians while secretly yearning for their downfall, he has the best lines in the movie and his accent increases the effect of the lines. His constable, who was also his classmate in school, provides good support with some funny kadi jokes(like his reason for carrying some items in his pocket).

Sarathkumar looks a bit old but shows vigor in the action sequences. We feel sorry for Nikitha who seems to have less to do than heroines usually have in action movies. After initially professing love for Sarathkumar, she completely disappears till she is needed to make him open up about his past. Mahadevan is adequate with his usual low-key villainy. Rajesh has an interesting character of an ex-military man who never fails to respect the national anthem. S.A.Rajkumar surprisingly comes up with tunes that dont bear his usual touch. Ragasiyamaai... is a catchy number.