Rangan (M.G.R) the very loving brother of Thangam, although solely a cart puller, goals of training his sister, to change into a physician. So, when he learns of his sister's love with Murali (Muthuraman), a physician, he will get them married, in a grand method. Murali's mom, after their marriage, learns that Thangam is the daughter of Velappan, her husband's (mill proprietor Karunakaran) assassin. Thangam is thrown out of the home. Rangan finds out that his father, who continues to be languishing in jail, had been falsely implicated. He vows to convey the actual culprits to guide. His fiancé Valli (Jayalalitha), helps him nab the murderers. It's proved finally that justice all the time wins.
