The following plot focuses on the Tamil version only.

The story takes place in Panimalai, a hill city, during the spring season. The film begins with RJ Balaji coming to Panimalai to be a guest of a live radio show. In the middle of the show, he starts coughing severely and suddenly loses his voice. He is diagnosed with a new type of virus called the mute flu that causes sudden muteness and sometimes even death.

Aravind is a sales representative working with a glue company. His dream is to become a radio jockey, and he even attends interviews with an FM station. As the mute flu spreads across the city, the state government sends Health Minister Sundaralingam to Panimalai to take care of the situation. The people are asked to undergo a medical checkup to check whether they are affected by the virus or not. Aravind goes to the hospital and meets Anjana, a junior doctor and attends the check up. While Anjana is testing Aravind, some young boys waiting for the test tease Anjana and in frustration, Anjana pokes a cotton bud into Aravinds' nose with which he starts choking and feels like vomiting, but is comforted by Anjana and they both start talking and here we are known more about Anjana, who believes that talking is the only cause of all the problems in the world and if people keep things to themselves, then things will be very fine. Anjana is in a relationship with Vinodh, a possessive guy who always commands her on what she should do and what she should wear. Anjana lives with her father and stepmother Vidhya. Since Anjana lost her mother at a young age, she is reluctant to accept Vidhya as her mother, though she is a sweet and caring woman and always maintains a distance from her. Vidhya is an aspiring writer who is trying to get her husband's attention and support to write her third book. Her husband finds no time to talk to her as he is too busy with his work.

Panimalai comes into the news for another issue, where "Nuclear Star" Bhoomesh, a film superstar who has gone to shoot one of his films, is being opposed by Mattai Ravi, a drunkard who is President of the Drinkers Association, over the issue of Bhoomesh showing drunkards in a bad light in his films. The Drinkers Association and Bhoomesh's fans, led by Ganesh, form groups to fight over this issue.

Aravind and Anjana begin a friendship, and he insists to her that if everything is spoken directly from the heart, then there would be no problem between anyone. He asks her to speak openly with Vinodh and sort out the difference of opinion between them. She does not agree to this, and Aravind challenges her that if he successfully stops the feud between Bhoomesh and Ravi just by means of speaking, Anjana should talk openly with Vinodh to sort out their issues. However Aravind hates Bhoomesh to core, even the photo of him makes Aravind feel nauseous & disgusting. They both agree on the challenge and mark a deadline day. Aravind tries so many ways to stop the feud between Bhoomesh's fans and the Drinkers Association, but it ends up in an even bitter fight. As time goes by, Aravind falls in love with Anjana, not knowing that she is engaged to Vinodh.

Aravind is brought up in an orphanage that belongs to Adhikesavan, a stubborn old man who is constantly asking the orphanage to be vacated so that he can rent it to richer tenants. Though Aravind helps the children in the orphanage by donating some of his money, it is not enough to save the orphanage. Aravind tries to speak to Adhikesavan and sort the issue, but the latter is too hesitant to speak with him. Aravind and his friend Sathish kidnap Adhikesavan and leave him in his son's house, making a close relationship.

The final report by the health organisation says that the dumb flu spreads only by means of speaking, and issues a speaking ban in the town. Everyone in the town tries to adjust to living with not speaking. Aravind conducts the meeting with the Drinkers Association and Bhoomesh's fans, and they reconcile. A cure for the illness is invented, but if the virus has already infected but has not removed the voice of a person, the cure has a 50% probability of a side effect that the patient might lose the ability to speak. The film ends with everyone getting cured, but Sundaralingam, who has been faking the illness being given cure medicine on the stage for a photo op, loses his voice for real.