Siddharth (Arjun) works as a General Manager of a five - Star Hotel owned by S.Ve Sekhar and his daughter is Lara , a foreign returned and an employee in the same hotel. Siddharth and Lara fall for each other. He has another face too. He murders all criminal lawyers who appear for the thug, corrupt politicians and other anti socials elements. First he murders cleverly the famous criminal lawyer Anadaraj who appears for a goonda by hitting him with a cricket ball and the police close the file as a case of accident. Then it was Saranraj's turn. He also gets killed and Nazar, an army Major is a witness to it. The killing spree continues. Lawyer Devan becomes the next in his target. Siddharth caught red-handed by Nazar is forced to narrate why he turned ruthless against all lawyers who misuse the law. The story unfolds in a flash back. His father (director P.Vasu) was an upright and honest judge who was brutally murdered by a local goon and contractor Muthupandi (Rajan.P.Dev) in a running train while he tries to appear on a case against the thug. His mother also dies in the attack and his only sister (Abhitha) escapes. Criminal lawyer (Devan) appears in the case and helps Muthupandi and his men to come out of the case. 
This incident makes Siddharth to become fixated to provide 'instant justice' to lawyers who argue and win cases of criminals. (So the catch line -- 'When Justice fails...' is justified). One day a lawyer from Delhi (Raghuvaran) comes to defend a rapist, as criminal lawyers in Chennai are frightened to take up the case. Siddharth plots to kill him but gets shocked when he finds out that the Delhi lawyer is none other than the husband of his lost sister. Now in the melodrama that sparks off between the two, Raghuvaran finds out that Siddharth is the culprit behind the recent murders. Despite all odds how Siddharth manages to kill Raghuvaran in the climax and justifies his action at the end forms the rest of the story.