Amar Deep features the story of Raja (Rajesh Khanna), who inherits the property of crime lord (Ashok Kumar), who had adopted him. He falls in love with Radha, his servant's daughter and desires to marry her. However, issues evolve when he discovers that Radha is love with Kishan (Vinod Mehra). Upset, he decides to get the two married and later hires Kishan for his oversea business. With Kishan traveling across cities, Raja decides to get close to Radha. Will Kishan realize Raja's evil motives?