Thangalakshmi, a wealthy and influential woman, plans a marriage for her daughter Abhinaya with an NRI in her native village, aiming to secure her daughter's future. However, her peace is disrupted by a persistent gang led by Paalpandi, who is later revealed to be Thangalakshmi’s own brother. This gang begins to stalk both Abhi and Thangalakshmi, creating a tense and dangerous atmosphere. To protect Abhi and ensure her safety until her marriage, a rogue named Kathhi—a man known for doing anything for money—is appointed as her bodyguard.
Paalpandi repeatedly tries to persuade Thangalakshmi to marry Abhi to his son, but his efforts prove unsuccessful. Meanwhile, a series of strange and violent events unfold: the stepfather and cousins of Kamaraj (a former District Collector and Thangalakshmi’s husband) release themselves after falsely claiming to have been wrongly imprisoned for his murder. They go on to kill the judge and public prosecutor involved in their jailing, intensifying the chaos. These relatives manipulate Thangalakshmi into believing they are innocent, and that Paalpandi is the true culprit—an assumption she has long suspected but is now convinced of.
Amidst these upheavals, Kathhi and Mani—Thangalakshmi’s assistant who secretly desires to marry Abhi—work humorously to foil her marriage plans. The groom, however, is kidnapped by Kamaraj’s relatives, who intend to kill him and blame Paalpandi for the crime. Kathhi intervenes with quick action, fighting off the goons and saving the groom, who then refuses to marry Abhi, respecting the wishes of his own parents to stay true to his commitments. This sequence of events leads to a tense confrontation at the marriage hall, where Paalpandi arrives with his men and presses Thangalakshmi to marry Abhi off to his son once more.
Refusing to succumb to pressure out of pride, Thangalakshmi compels Abhi and Kathhi to marry and taunts Paalpandi by claiming she has met her promise. At this moment, Paalpandi reveals a shocking truth: Kathhi is actually his son, Kathiresan, and his real name is Kathiresan MBA. The revelation leaves Abhi and Thangalakshmi stunned, and they try to accuse him of kidnapping and intimidation, but Kathiresan cleverly produces a video recording of the marriage hall events, clearing his name.
Desperate to escape, Abhi and Thangalakshmi attempt to run off to Bangkok, but Kathiresan challenges Thangalakshmi—saying that he will make Abhi accept him as her husband if she allows her to stay in his house for seven days. He also proposes that he might try to physically engage with her without her consent, adding an unsettling twist to his character.
Initially, Abhi faces cold hostility from her maternal relatives, but she gradually begins to see the caring and genuine nature of Kathiresan and his family. Despite Thangalakshmi’s repeated efforts to separate them, their bond deepens, and she begins to realize Kathiresan’s innocence and kindness. As the story reaches its climax, Kamaraj’s relatives attempt to murder Thangalakshmi, but she manages to contact Kathiresan. He arrives just in time, rescuing her but gets stabbed during the fight.
The villains, realizing the truth, are confronted by Kathiresan, who fights fiercely and kills them, ensuring justice. The climax ends with Thangalakshmi acknowledging her mistakes, reunited with her family, and finding happiness with Abhi and Kathiresan. Their story concludes on a joyful note, emphasizing themes of love, forgiveness, and the power of truth in overcoming deception and adversity.
