Thirupaachi

A city suitor proposes to Karpagam. Giri accepts the match and places his sister's happiness above his own. The moment establishes his protective nature and the start of his journey into Chennai's dangerous world.

Giri accompanies Karpagam and her city groom to Chennai. The urban journey exposes him to a harsher social landscape and foreshadows the conflicts he'll face. He takes on a guardian role as they navigate the city together.

In Central Chennai, Giri intervenes to save a court witness from Pattasu Balu's gang. The rescue signals his willingness to confront powerful criminals directly. This act marks the beginning of his clashes with Balu and his network.

Giri discovers Pan Parag Ravi, a formidable gangster ruling North Chennai. Ravi's activities threaten Karpagam's husband's canteen business and expand the reach of crime. Giri begins plotting how to dismantle Ravi and his circle.

During an altercation at a theatre, Kannappan is murdered by Saniyan Sagadai. The killing deeply unsettles Giri and intensifies his resolve to wipe out the city’s gangsters. The event signals the start of an escalating gang war.

Following Kannappan's funeral, Karpagam's husband urges Giri to return home for his sister's happiness. Giri refuses to abandon his mission and decides to stay in Chennai to continue the fight against crime. The politics of protection and loyalty deepen.

After the funeral, Giri leaves his hometown, claiming a job with a cloth manufacturing company in Erode. In truth, he remains in Chennai with the intent to finish off the gangsters. His resolve hardens as the city becomes his battleground.

Giri directly contacts Sagadai and informs him of his intent to kill him, while also reaching out to ACP Raj Guru to eradicate the city’s crime network. The conversations reveal a vigilante aiming to impose his own form of justice. The stage is set for a city-wide clash.

Inspector Veluchamy, initially wary of Giri, helps after his son Arun is killed by Balu. He provides a list with the profiles of leading gangsters across the city. Giri uses this intelligence to plan targeted eliminations, beginning with Balu.

Giri provokes Ravi to kill his own brother and Ravi hides in a politician's house to escape. Ravi damages the politician’s property to mislead the police into believing an attack occurred. The police subsequently tighten security around the politician.

Giri mobilizes a crowd of people cheated by a fraudulent financier sheltering in the politician's place. With the rally as cover, he infiltrates Ravi's fort and kills Ravi. The city watches as the lines between law and vigilantism blur, with few willing to betray him.

Raj questions those involved in the rally, but fear and loyalty prevent anyone from speaking. Raj's daughter refuses to reveal Giri's identity because he once saved her from Balu. The vigilante's image grows as his actions go unpunished by official channels.

Giri uses Sagadai's protection by a mass of thugs to dismantle the city’s crime network. He disguises himself as a cop and infiltrates Sagadai's fort with Veluchamy's aid. Raj orders his squad to strike the thugs, worsening the power struggle between police and criminals.

Giri confronts a thug and forces him to wear a police uniform, killing him and creating confusion among Sagadai’s defenses. Raj and the police annihilate the remaining thugs, but Giri's plan remains hidden to many. In a decisive move, Giri stabs Sagadai and throws him to the ground just before the New Year, avenging Kannappan's death.

In the aftermath, Giri reunites with Subha, Karpagam, and her husband. The city’s crime networks have been shaken, and Giri's life remains intertwined with Chennai as he protects his loved ones. The ending emphasizes his unwavering commitment to family and city alike.