In an unnamed village, a teenage Raayan grows up under the care of his family: his parents, his brothers Manickam and Muthu, and a newborn sister Durga, whom he adores. When his parents vanish on the pretext of traveling to Chennai, Raayan steps up to protect and care for his siblings. A priest tries to abduct Durga, and in the ensuing struggle, Raayan kills him. The siblings flee to the city and are taken in by a market businessman named Sekhar who becomes their guardian and Raayan's employer.
Years later, Raayan runs a food truck in North Chennai. Manickam is a college student, while Muthu—a hot-headed alcoholic—falls in love with Meghalai. Sekhar remains a steady, protective presence for the family, supporting them as best as he can.
Two rival gangsters, Durai and Sethuraman 'Sethu', feud after Durai killed Sethu's father. The newly transferred police commissioner R. Sargunam bears a personal enmity with Durai and schemes to set Sethu and Durai against each other, hoping to eliminate both in an encounter. When Sargunam sends his men to ambush Sethu, Sethu retaliates by killing them, and blames Durai for the attack. Durai discovers that Muthu was present, leading him to demand that Raayan turn over Muthu within 24 hours. Raayan, however, refuses to betray his family, and he, Muthu, and Manickam retaliate by killing Durai and his gang.
Seeing Durai's death, Sethu invites Raayan to join his side and promises protection for him and his family, but Raayan declines. Sethu then attempts to assassinate Raayan by sending his henchmen, but one surviving member returns to Sethu with news that Raayan has killed all his men. Around this time, Raayan plans Durga's wedding and faces a money crunch; he considers pledging his profitable mobile hotel and their bank savings to the groom's family.
On the eve of the wedding, Raayan tries to strike at Sethu by entering Annam's house, Sethu's second wife, but Durga is abducted by Guru, a henchman in Sethu's orbit, and Durga is subjected to a brutal assault. Meanwhile, Muthu and Manickam, unable to find steady work, have been secretly helping Sethu to support the household, and they are shocked to realize the target is their own brother. Durga, after escaping Guru, returns to Raayan and Durga is healed with help from Sekhar. Guru is killed by Durga in the confrontation that follows.
Meghalai gives birth to Muthu's child, deepening the stakes for the family as tensions rise. Manickam seeks amends, and Sekhar arranges a meeting with Raayan to plead for mercy; but Sethu manipulates Manickam and uses Sekhar to reveal Raayan's whereabouts, leaving Sekhar dead and Raayan and Durga forced to go on the run. Meanwhile, R. Sargunam adapts his plan, offering a deal: eliminate Sethu and his gang in exchange for Raayan and Durga obtaining freedom, safety, and a new identity.
During Bhogi celebrations, Durga stabs and kills Manickam for betraying Raayan. In the brutal final clash, Raayan destroys Sethu and his gang, and, with heavy heart, kills Muthu as well. The next day, Meghalai relinquishes her child, and Raayan and Durga decide to leave behind the violence and start anew in Coimbatore, seeking a peaceful life away from the bloodshed.
