Kodi and Anbu are twin brothers whose lives are deeply rooted in Pollachi’s political landscape from birth. Their mute father, Murugan, a low-rung Democratic party worker, helps name them at the party president’s urging and pulls them into the rough world of politics before he self-immolates in protest against a factory whose toxic mercury waste has ruined lives in 1995. Anbu, a college professor, remains apolitical, even as Kodi grows up immersed in politics with his friend Bhagat Singh and a romance with Rudhra, who, like him, has spent her life in politics but currently belongs to the opposing Republican party that holds power.
Despite opposition from ex-minister Marimuthu, Kodi earns the role of District Youth Wing Organizer for the Coimbatore district because of his growing popularity and diligent work. One day, while fighting on the streets with opposition forces, he accidentally knocks over a trolley of eggs that Malathi is trying to sell. She chases after him, later meets Anbu at a college cafeteria, initially mistaking him for Kodi, before discovering his twin. Anbu and Malathi fall in love, and she shares with him how factories near her village dump mercury waste, affecting the villagers’ health. Anbu grows worried and tells Kodi about it.
Rudhra feels confined by stereotypes that label her as inferior in her party simply because she is a woman and poor. One night, she overhears that Arivazhagan, the State education minister from Coimbatore, had dropped out of school and falsified his nominations. She passes this information to the Democratic party, which files suit against the minister; the minister loses and is disqualified, triggering by-elections for the Pollachi constituency. Rudhra befriends the ex-minister, becomes the interim District Secretary, and then ejects him.
The Democratic party anticipates the by-elections with optimism, even though the ruling party has won them for the past 25 years regardless of who is in power. Kodi meets the party’s supremo, who tells him they will discuss the opposition’s scandal after the by-elections. Meanwhile, Anbu supplies documents about the mercury waste to Kodi, who uncovers that his ex-minister, Marimuthu, and the entire Democratic leadership bear responsibility for what happened to the villagers. Feeling betrayed, Kodi shares this with Rudhra, who exposes it in a public speech.
The Democratic leader, furious, plots to keep Kodi quiet by nominating him as their by-election candidate—now pitted against Rudhra. When the Republican party learns of their relationship, they press Rudhra to drop out. Photos of their vacations leak online, stalling the campaign. The Chief Minister, Vijayakumar, orders Rudhra to steer the campaign within a day or replace the candidate. A despondent Rudhra asks Kodi to meet her in the woods; she explains that the ex-minister stands in the way of her success. They are ambushed by goons Arivazhagan sent to kill Rudhra, but Kodi defeats them. Rudhra suddenly turns on him, apologizes, and tells him that he was her last obstacle. Devastated, Kodi resolves to sacrifice himself, and the by-elections are canceled for three months after the candidate’s death.
Anbu confronts party members and is expelled. Rudhra meets Kodi’s family and says she can secure Anbu’s candidacy for MLA. The mother rejects it, but Anbu accepts the risk and wins the by-election unopposed. Rudhra is made the full-time District Secretary, and as a bonus, an MP of the Rajya Sabha. Anbu, now congratulating her, bears a transformed look and demeanor that mirrors Kodi’s, much to Rudhra’s dismay. He also hints at being deeply involved in his brother’s murder and the mercury waste case.
In the forest, Kotraivel, a member of the Democratic party (played by Raja Simman), discovers a hidden camera that records Rudhra killing Kodi and uses this to threaten her, demanding she address the mercury waste issue. Rudhra leverages the Crime Branch inspector, V. Ravichandran (not linked here due to uncertain casting), to erase the evidence and kill Kotraivel, but she fears that Anbu might uncover everything as he carries crucial documents to the court.
To prevent discovery, Rudhra abducts her mother and Bhagat and compels Anbu to come to the factory. Anbu realizes that Rudhra killed Kodi and confronts her, engaging in a brutal fight with Rudhra’s goons, Kotraivel, and Marimuthu. Though he gains the upper hand, his mother pleas for restraint, and the trio departs. Bhagat Singh, whose loyalty once hoped for their happiness, impales Rudhra with an iron rod, lamenting that he wished for Rudhra and Kodi to live happily but that dream was ruined. He leaves her for dead, closing a devastating arc of betrayal, bloodshed, and tangled loyalties.
