What’s it about :
Sega literally means a burning flame. And that's what the movie is all about. Its a flame burning in people and based on their characters, it can be a flame of love, loyalty, revenge, greed, lust or hatred. The story of Sega revolves around two brothers, Karthik (Nani) and his elder brother Balaji (Mutthu). The movie is a dark and intense portrayal of the lower strata of society and vices like prostitution and drugs that are now prevalent in the seedier parts of any big city. The story starts off with Karthik and Balaji's mother on the deathbed. Their father 'Jyothi Anna' (Shimmore) is a thug who abuses and harasses the family. Fed up with life, Balaji's mother commits suicide and Balaji unknowingly helps his mother kill herself. This guilt hangs over Balaji for the rest of his life and drives him towards intensely hating his father. Karthik meanwhile, is childhood friends with his neighbour Vishnu (Karthik Kumar) and Revathi (Nitya Menon). They grow up together and Karthik earns his living as a painter under Revathi's dad and Vishnu inherits an automobile repair shop from his father. There is a nice romantic track between Revathi and Karthik.
Vishnu is projected as an easy going Casanova and he is always on the lookout for a good 'deal'. A few chance encounters with Vani (Bindhu Madhavi), a prostitute, soon leads to a budding romance between the two.Into this scenario enters 'Jyothi Anna', who has now graduated from a street thug into a pimp and a drug peddler with considerable influence. Jyothi Anna stuns Vishnu with his display of money and influence and soon entices Vishnu into carrying out his shady activities.
Karthik, who dearly loves Vishnu and is ready to do anything for his sake, is soon dragged into this vortex of crime and drugs. A drug peddling mission goes bust and Karthik & Vishnu find themselves on the run from both the warring drug factions of the city, headed by Ammaji and Bai respectively.
A few twists and double crosses later, Vishnu ends up being dead and Karthik is arrested for his murder. Balaji and Revathi do not believe the accusations against Karthik and each mount their own operations to uncover the truth. Balaji goes after his father Jyothy Anna and Ammaji and learns a few shocking truths regarding the real motive behind Vishnu's murder. The rest of the story is all about how each of the main characters quench their respective Sega (of hatred, revenge etc). Does Karthik come out clean? Is he really responsible for Vishnu's death? Watch the movie to find out the answers. The climax shows that life comes a full circle for all the characters.