For instance, the meaning of the Dagny-Rearden romance in Atlas Shrugged is that their shared ideas, values, and struggle is the root of their love. Consider what a non-plot writer would have done with this material, Dagny would come to Rearden's office, they would start talking, and suddenly he would draw her into his arms and they would kiss. This is realistic, it can happen—but it does not have much dramatic value. The same scene could have happened between any two people, including villains such as James Taggart and Betty Pope.
By contrast, in Atlas Shrugged I bring about Dagny and Rearden's love scene at the height of their mutual triumph, in connection with the achievement which unites their careers: the opening of the John Galt Line. I make them admit their love during an event which presents in action the ideas and values they have in common. This is an example of presenting an issue in plot terms.
Or take the quarry scene in The Fountainhead, where Dominique meets Roark. She is an extreme hero-worshiper; she has declared that she will never fall in love except with someone great; and she does not want to find a great man because she thinks he would be doomed. If, while researching tree of her newspaper columns, she had met Roark as a rising architect, that would not have been dramatic. But it is dramatic for her to meet the ideal man at the bottom, as nothing but a quarry worker. She had feared that the world would crush a hero—and the scene brings her face-to-face with the fact that no matter what the world does to him, a hero is a value, and one she cannot resist.
Ayn Rand, "The Art of Fiction", p. 26-27.