'Urimai kural' is the story of two loving brothers, Sundaram and Gopi (M.G.R.). Sundaram is a simple farmer who lives happily with his wife, daughter and brother Gopi. He takes loan against his property from Dorai's (Nambiar's) father. Dorai wants to marry Radha (Lata), the village beauty, but she is already in love with Gopi. Much against her wishes, her marriage is fixed with Dorai, but both Gopi and Radha elope on the night before her marriage and get married. Sundaram refuses to accept them as he feels that Gopi has marred the family name. He erects a wall in the house and refuses to even see the face of his loving brother Gopi. Seething with vengeance, Dorai gives both the brothers innumerable problems and literally brings them on the streets when Sundaram is unable to repay the loan. How the brothers reunite to face the adversity and fight these problems jointly is what the rest of the movie is all about.