Dilip Kumar saves Nargis from a riding accident and falls in love with her.Nargis is already betrothed to Raj Kapoor but fails to mention this to Dilip Kumar(no reason for mentioning).She regards him as a friend.Dilip only gets to know about Raj when the latter returns from his studies abroad.Raj marries Nargis, and Dilip moves out of their lives, but not before he is forced to admit to Nargis that he had fallen in love with her.Nargis suffers and this ruins her marriage with Raj.The film, made in 1949 by Mehboob Khan tried to show the effect of 'modern'lifestyle on family life.Nargis represented the 'fast' 'modernised' Indian woman to whom friendship with the man who had saved her, meant just that.Love and friendship are two separate feelings.Nargis wonders if she has in any way encouraged Dilip to make him feel the way he does.Dilip tells her that it was he who had made the 'mistake'. Nargis however cannot stop feeling guilty.Dilip Kumar is absolutely brilliant. Watch the song 'Darna muhabbat karle', where Nargis and Cuckoo sing while Dilip plays the piano. He has eyes only for Nargis.You realise how much he is in love with her. A better performance will not be seen.As a romantic actor Dilip has no match.