An elderly Krishnan vomits blood and passes away at his house. His son Suriya, an Indian Army Major, is on his way to Kashmir on a rescue mission to rescue a journalist kidnapped by terrorists. He learns of his father's demise and tearfully reminisces memories of his past with his father.

Krishnan and Malini are both students at Madras Christian College in the 1970s. They fall in love and later get married; Suriya and his sister Shriya are born. Krishnan and Suriya get along more as friends than a father-son duo. Years later, after completing his exams in Trichy, Suriya meets Meghna on a train back home and falls head over heels for her, but Meghna doesn't believe in love at first sight. Suriya soon learns that she is leaving for California to pursue her master's degree.

Meanwhile, Krishnan suffers his first heart attack due to chain smoking. Reality strikes Suriya that he needs to be responsible in order to take care of his family. He starts a design firm with his friends and also performs at concerts to earn money. Suriya and his sister earn enough to complete their father's dream home. Later, taking his father's advice, Suriya tracks down Meghna in San Francisco. Though surprised by his presence, Meghna makes him stay with her. She eventually starts to fall in love with him. Convinced that Suriya is the right guy and also because her father would accept a person like him, Meghna proposes to Suriya much to his and his family's delight. She then leaves for Oklahoma City on a project. However, the Oklahoma City bombing takes place, in which Meghna is killed, leaving Suriya hysterical and heartbroken.

A depressed Suriya returns to India and meets a businessman Shankar Menon on the way. He consoles and encourages him. Weeks pass by; Suriya tries hanging out with friends, and meets Priya, Shriya's friend. She proposes to Suriya and confesses that she was in love right from their childhood, but Suriya does not reciprocate right away; in fact, her proposal just causes Suriya to have a painful relapse of Meghna's memories to the point that he starts using drugs and alcohol to ease his pain. Malini and Krishnan find out about his drug abuse and lock him up in his room to rehabilitate him. Once he starts withdrawing, Malini encourages Suriya to go on a rejuvenating trip but on a condition that he returns home. Suriya travels to Kashmir, where he learns that Aditya, Shankar Menon's son, has been kidnapped in Delhi. He decides to find Aditya and after days of roaming the city and investigating, he finds Dabbu Malik who directs him to the kidnapper, Asad. With no preparation and falling into all mess alone, he overpowers them intelligently and rescues Aditya. He receives critical praise from around the country and from his family upon his return home.

Suriya realizes that the only way to forget the pain of Meghna's memories is to train his body and prepare for bigger things. He goes on a strict workout and joins the Indian army as a commissioned officer. Now as Major K. Suriya, after six years, he meets Priya in Dehradun. She proposes again and this time he reciprocates; they get married and eventually have a son. Suddenly, Krishnan is diagnosed with throat cancer due to his smoking habit and is given a year to live. A few days later, Suriya is called upon to go on a mission to rescue a journalist, which brings the scene back to the present day.

The military mission is completed successfully and Suriya returns home victorious and tearfully honours Krishnan and performs his last rites. Suriya, Shriya, Malini and Priya pour Krishnan's ashes into the sea and Malini encourages Suriya to move on in life with his family by telling him that he is "the conqueror of a thousand elephants" just like his father, who conquered Malini and made her his life. Suriya looks back and says that his father is still with them. The film ends with an image of Krishnan smiling at them and walking gleefully along the shores.