Sethupathi, Kamal Haasan, is an honest police officer living with his pregnant wife Kaveri Srividya. When he brings down four powerfully connected criminals — Dharmaraj, Francis Anbarasu, Nallasivam, and Satyamoorthy — they slip through the system and vow to make him pay. In a brutal turn of fate, one night they kill Sethupathi and poison Kaveri. Yet Kaveri fights for her life, escaping with the help of Muniyamma Manorama. In the aftermath, she gives birth to twins, but fate parts them: one boy, Raja, grows up under Muniyamma’s care as a skilled mechanic; the other, Appu, is a dwarf who spends his childhood in a traveling circus with his mother.
Years pass, and Appu discovers first love with Mano Rupini. He misreads her invitation to elope as an escape for the two of them, while Mano’s intended marriage is with her fiancé Vincent Anand, whom her father disapproves of. Heartache gnaws at Appu, and he even contemplates suicide when his height becomes a symbol of his grievance. His mother comforts him and reveals a haunting possibility: the dwarfism in his family might trace back to the poison that harmed Kaveri while she carried him. The revelation steels Appu’s resolve to uncover the truth about his father’s murder and seek vengeance.
Across the years, Raja falls for Janaki, who is Satyamoorthy’s daughter Jaishankar. As Raja’s resemblance to Sethupathi grows more obvious, Satyamoorthy and his accomplices become wary, sensing that the detective’s son could expose their past misdeeds. The path to vengeance tightens its grip when Appu lures Francis Anbarasu, Delhi Ganesh, into an abandoned building and ends him with a carefully crafted Rube Goldberg machine. Francis’ body slides into a lorry (driven by a Lorry Driver Kavithalaya Krishnan) hidden under hay, and Raja and Janaki find themselves unknowingly sharing the same ride, oblivious to the gruesome cargo.
A separate strike follows: Nallasivam, Nassar, is killed on a golf course by Appu using a circus tiger. The caddie glimpses Appu’s face and spots the tiger’s tail from a distance, tugging the investigation toward Raja, who is performing in a tiger costume during a festival. Janaki’s trust wavers, and she breaks up with Raja when she learns he is a suspect. The postmortem eventually reveals real tiger wounds, clearing Raja for the moment.
Raja races to Janaki’s home to reconcile, but the inspector trails him. While Raja talks with Janaki, Appu tricks Satyamoorthy into killing himself with a circus handgun that shoots backwards. Appu escapes, but Raja and Janaki reach Satyamoorthy’s room just moments before the inspector does. Janaki faints at the sight of her father’s body, and the inspector grows convinced that Raja is the shooter. A tense chase follows, and Raja becomes a fugitive. In a crowded market, he grabs a woman hostage to demand a clear path, not realizing the hostage is his own mother, Kaveri. When the crowd finally retreats, Raja releases Kaveri and flees. Kaveri realizes that Raja is her other son and seeks out Muniyamma. They piece together that the murders were the work of Appu, and Appu overhears their confession.
Dharmaraj, convinced that Raja is avenging his father, abducts Muniyamma and Kaveri and threatens to kill them unless Raja surrenders. Appu escapes, helps Raja elude the law, and reveals everything. The two brothers reunite in a daring mission to the circus, where the women are held captive. In the ensuing confrontation, Appu and Raja take on Dharmaraj’s henchmen and overpower them. Dharmaraj is left hanging by a rope, and with Kaveri’s quiet blessing, Appu shoots the rope, releasing him to a mauling by circus lions. Appu eventually surrenders to the police, and Raja and Janaki’s bond is finally restored.
In this sprawling tale of kin, loyalty, and vengeance, the twins’ intertwined fates drive a vigilante justice that blurs the lines between attacker and protector. The film builds its drama through motifs of mistaken identity, revenge born from tragedy, and the unbreakable pull of family, all while painting a vivid portrait of a man who chooses to fight back against a world that tried to destroy him.
