Politics have been a part of Kodi's life ever since his birth in Pollachi. Kodi's father Murugan was a low-rung Democratic party worker, bringing him up in the world of politics before self-immolating in protest against a factory whose toxic mercury waste had ruined lives in the locality. Kodi's twin brother Anbu is the complete opposite of him – an engineering college professor and not political at all. Kodi grows up being political with his friend Bhagat, and is in a relationship with Rudra who, like Kodi, has been a politician all her life but with the opposing Republican party currently in power.

While fighting members of the opposition on the street one day, Kodi breaks a trolley of eggs that Malathi is trying to sell to a shopkeeper. She chases after him to no avail, before leaving for an appointment at a college cafeteria where she has an interview for a contract to sell eggs. She comes across Anbu, mistaking him for Kodi, before finding out about his twin brother. Anbu and Malathi fall in love. Later on, Malathi tells him about how the factories near her village dump all of their mercury waste where people live, impacting the lives of the villagers negatively. Anbu is worried and tells Kodi.

Meanwhile, Rudra is frustrated about being stereotyped as lower down in her party because she is a woman. She overhears that Arivazhagan, the State education minister from the Coimbatore district, actually dropped out of school and falsified his election nominations. She tips this information off to the Democratic party, who file a suit against the Minister. The Minister loses the case and is disqualified from his position, and the by-elections are announced for the Pollachi constituency. Rudra befriends the ex-minister, becomes the interim D.S, and then kicks him out.

The Democratic party are excited for the by-elections despite the Republicans winning for the last 25 years. Kodi meets his Party Supremo, who tells him that they will talk about the opposition's scandal but after the by-elections. Meanwhile, Anbu provides the documents about the mercury waste to Kodi, who then finds out that his ex-minister and party senior Marimuthu, and the entire Democratic party, are responsible for what happened to the villagers affected by the factory, as they were the ruling party at the time. Feeling betrayed, he shares this with Rudra in confidence, who brings it up at her next public speech.

Enraged and embarrassed, the Democratic leader plots to keep Kodi silent by announcing him as their by-election candidate – now running right against Rudra. When the Republican party finds out about Kodi and Rudra's relationship, they start pressuring her to give up her candidacy. A depressed Rudra asks Kodi to meet her in the woods to talk, and she tells him about the ex-minister standing in her way to success before she eliminated him. They get ambushed by goons that Arivazhagan sent to kill Rudra. Rudra suddenly stabs Kodi, apologises, and tells him that he was her last obstacle. Kodi is betrayed again but decides to die for her, and the by-elections are cancelled as they no longer have one of their candidates.

Rudra meets Kodi's family after the funeral and tells them that her party is willing to give Kodi's brother Anbu the position of MLA. Their mother declines it angrily, but Anbu accepts it and wins the by-election unopposed. Rudra is made the official District Secretary and an MP of Rajya Sabha. Anbu comes to congratulate her; his look and body language are now completely changed to match his brother Kodi's, much to Rudra's dismay. Anbu lets her know that he is very invested and interested in his brother's murder as well as the mercury waste issue.

Kotraivel, a member of the Democratic party, finds a forest camera hidden in the woods that recorded Rudra killing Kodi. He threatens Rudra with this, and tells her to fix the mercury waste issue. Rudra uses Crime Branch Inspector V. Ravichandran as a pawn to destroy the evidence and kill Kotraivel, but is still afraid of Anbu finding out about everything as he was taking the documents about the factory to the court.

In an attempt to stop him, Rudra kidnaps his mother and Bhagat, and tells Anbu to come to the factory. Anbu and Rudra's goons fight Kotraivel and Marimuthu, resulting in Anbu winning. He came to the factory with the intention to kill Rudra, but his mother tells him that it is not worth it and to let her go. As they leave, Bhagat impales Rudra with an iron rod and tells her she never deserved Kodi.