Plot
Ramanaa begins with the abduction of 15 Tahsildars across various parts of Tamil Nadu. After three days in captivity, 14 officers are released, but one's body is found in Trichy. The police find a tape recording and a file on the dead officer's body that provide significant evidence concerning the kidnapping and subsequent murder. The files suggest that the crimes were committed by members of the self-proclaimed "Anti-Corruption Force" (ACF), a citizen militia seeking to eliminate corruption through vigilante acts. The group proclaims that they will kidnap top 15 corrupt officials in each department, keep them in captivity for a week and kill the most corrupt one.
The film's setting then shifts to Dr M. Ramanaa, a mild-mannered professor at National College in Chennai, who lives in a house with four adopted kids. While treating his adopted child at a big private hospital, Ramanaa discovers that the officials at the facility are engaging in extortion and fraud. After sending his kids home, he goes to the Govt hospital, brings a recently dead poor man's body to the private hospital and tricks them into treating a dead man. The hospital staff fall for the trick and try to extort a heavy sum using the body. Ramanaa pays all the fees and collects all the documents. When the doctors inform him that the patient is dead, he reveals the trick. Rishi, who is the hospital's heir bargains with him, but eventually pays Ramanaa two millions rupees. Ramanaa takes the money he paid the hospital and gives the remaining huge sum to the poor man's family. He also sends copies of the reports to the incoming President of India Dr A.P.J Abdul kalam. Due to government pressure the hospital and college are closed off.
Rishi commits suicide when he is about to be arrested. His grief-stricken father, a big and powerful construction magnate named Bhadrinarayanan, returns from Mumbai and vows to take revenge on the man responsible for his son's death. Meanwhile, the ACF goes on kidnapping the top 15 corrupt officials each month for 4 months and then killing the #1. Those officials include officials from transport, PWD, revenue, sports, health, etc. Then, suddenly, Devaki, a college girl and friend of Ramana's kids, finds out about him being the leader of the ACF. She questions him about this immoral activity.
Seven years ago, Ramana was a college professor with a small cute family, of him, his nine-month pregnant wife Chithra, and his daughter. During the festival of Deepavali, Ramanaa's apartment building collapses due to heavy construction work nearby, killing many residents including Chitra and his daughter. Recovering from the incident, he demands to know who was responsible for the building's collapse. He discovers that the building was built and owned by Bhadrinarayanan, who knowingly constructed the complex on loose soil. When Ramanaa confronts the District Council with evidence, Bhadrinarayanan walks in and boasts about all the bribes he has thrown to the top district officials including the collector. He gives Ramanaa a chance to call any two top officials in the state and get him arrested, but both the officials who are called immediately hang up. Frustrated, Ramanaa seals the room and attacks all officers, and as he is about to kill Bhadrinarayanan, he is beaten badly by his men, and is thrown on a highway. He is then rescued by National college students, who were on a trip. In response to Bhadrinarayanan's actions, and the general corruption in the region, Ramanaa forms the Anti-Corruption Force (ACF).
Meanwhile, a local police constable, frustrated for being not promoted, as he could not bribe officials, begins secretly building the case against the ACF. The constable eventually realizes that the ACF is primarily composed of people who do not take bribes. He visits multiple revenue offices, but his superiors neglect him due to him being their low associate. Then, a message comes saying that civil supply officers are going to be taken. All corrupt officials try to get police protection by proving their corruption, but at the last moment, the ACF switches to the Police department. All corrupt civil supply officers are immediately arrested, and the government promises to employ 25,000 youngsters within a week. 15 district police Superintendent of Police are kidnapped. The police officer is killed, and everyone is frustrated. A Punjabi IPS officer is flown from Delhi to head the case.
Meanwhile, Bhadrinarayanan is trying to re-corrupt the officials he comes into contact. As the final stroke, the top 15 dons are kidnapped. Ramanaa personally comes to Bhadrinarayanan. As was done to him, he gives the same lifeline to Bhadri, to call any two people within India. This time, Bhadrinarayanan fails and is kidnapped and later killed. Then, the constable reveals his plan to his superiors, and the IPS officer is delighted.
The officer takes swift action against them. The ACF members are captured and tortured by the police but refuse to reveal Ramanaa's identity. Ramanaa is overcome with guilt over his students' sacrifice and surrenders himself, on the condition that all the other members of the ACF be released. He is tried and convicted of being the mastermind organizer behind the murders of Bhadrinarayanan and 5 other government officials. He does not reject the accusations and is swiftly sentenced to death. He accepts the sentence and refuses to appeal to higher courts.
Public pressure from the sympathetic community and family makes the Chief Minister of Tamilnadu to visit Ramanaa in prison, and he offers Ramanaa a pardon. However, Ramanaa refuses, stating that only he must face the final consequences of his actions. He asks for a covert visit to his meet his children. He meets them when they are asleep and bids them a teary adieu. Students pour into the city and tensions build up. The government asks Ramanaa to give a speech to control the people. The next day Ramanaa appeals to the public and asks them to avoid corruption at all costs. Minutes later he is hanged. The constable is offered a promotion for his role in disbanding the ACF, but he refuses out of guilt.
