Raja, terrified of marriage, reluctantly shelters Priya Mahalakshmi when she runs away to avoid an arranged marriage. Pretending to be his lover, she wins over Raja's parents, who secretly arrange their wedding. Enraged upon discovering this on their engagement day, Raja kicks her out, only to find a photo revealing she is the Priya he has loved since college.
In a flashback, college-aged Priya, a die-hard fan of Raja's writing, confesses her love in the dark. However, when the lights return, Raja mistakenly believes another girl, nicknamed Thayir Saatham, confessed. They grow close while Thayir Saatham secretly helps Priya. Meanwhile, Bhavani, a thug infatuated with Priya, clashes with Raja. When Thayir Saatham tries to reveal the truth, Bhavani attempts to rape her, eventually throwing her from a car to her death, leaving Raja traumatized.
In the present, Raja refuses to marry Priya. As she waits for a train, Raja spots Bhavani boarding. Enraged, Raja boards the train, kills Bhavani, and finally reunites with Priya.