This film tells the story of two friends and the parallel events in their lives. Although Rathnam states officially that this film is not a true story, it is generally believed that it was inspired by the real life stories of M. R. Karunanidhi and MGR during the beginning days of the DMK and their respective film careers.
Everyone always calls this film a "documentary" and tends to emphasize the fact that it supposedly tells the story of Karunanidhi and MGR. I think this film has very little to do with politics. It goes beyond the popular perception of two famous political figures in TN and tells their personal stories and attempts to disconnect these two characters in the movie from the superficial symbols of power we may perceive them as.
People that stubbornly hold onto to the idea that this film is about former Tamil Nadu chief ministers Karunanidhi and MGR (M.G. Ramachandran) will most probably not enjoy this film as much as people who view it as a drama about two ordinary men who turned out to do extraordinary things.
Some of the finer points in the movie are the unsaid words between Mohanlal and Prakash Raj (not their role in politics!). All the invisible dialog that goes on between the two of them is reflected in the background music. Mohanlal plays Anand with a high level of sensitivity. Prakash Raj is also brilliant. Good, controlled performances from the rest of the cast. This film also has two wonderful songs--"Narumugaye" & "Poo Kodiyin Punnagai." Both have amazing lyrics by Vairamuthu and good visuals, as well. Santosh Sivan's camera-work is spectacular, as usual. He impresses in a nicely-captured, post-lovemaking scene with Tabu and Prakash Raj.