Balasubramanian alias Balu (Rajinikanth) is an absent-minded but kind-hearted Tamil college Professor. He lives with his younger brother Raju (Prabhu Ganesan), his maternal uncle (V. K. Ramaswamy (actor)) and his cousin Sumathi (Suhasini Maniratnam), who is also his love interest. Raju, who studies in the same college that Balu works, is short-tempered, rowdyish and a drunkard, spoiled by Balu's and Sumathi's pamperings. He frequently gets into fights with a fellow student Raghupathy (Nassar (actor)), whose father owns the college. Balu fails in several attempts to reform Raju. One night, Balu is accidentally killed when he tries to intervene in one of the fights between Raju and Raghupathy. Before dying, Balu asks Raju to ensure that he can find another person who can marry Sumathi as he does not want her to suffer after his death, to which Raju agrees with a heavy heart. Balu's demise marks a turning point for Raju, who vows never to get angry and drink again. Sumathi, who is devastated at Balu's death, goes into depression, dons the garb of a widow and vows never to marry. To ensure that Sumathi gets over Balu, Raju and Sumathi move to Bangalore, where Raju takes up a job at a garage owned by Devi (Kushboo Sundar).