The film is set in the early 1900s. It tells the story of a pretty and independent young woman, Ray Smith, who lives in Cincinnati. She has many suitors, none of whom she takes seriously. One day she meets an extremely charming and handsome banker named Walter Louis Saxel, and they fall immediately into a strong attraction, which for her is real love. After a few days of closeness she is shocked when he tells her he is already engaged to someone else. Nonetheless, the two of them very nearly marry one another on an impulse, but they are prevented from doing so by arbitrary external forces.

After five years, they meet once again, by chance, in New York City. The banker is now married with two children (Richard and Elizabeth) and is extremely successful in his career, but Ray and he still share the same strong attraction. Ray loves him so much that she gives up her career in dress design and becomes his kept mistress, seeing him only when it is convenient for him. Walter keeps up the appearance of a "happy marriage" and never considers divorcing his wife, whose father is his boss at the banking company.

Ray's loyalty to Walter collapses only once, when he fails to contact her after he has been on an extended trip to Europe with his wife. Ray goes back to Ohio and agrees to marry Curt, an attractive and good-hearted man who proposed to her many times in their youth. However, Walter travels to Ohio to find her, and is able to persuade her to return with him.

Once Walter's children reach adulthood they understand who Ray is, and they despise her. People in Walter's social circle also point condemning fingers at Ray, who suffers all this with patience and fortitude.

In old age, dying of a stroke in his grand home, Walter's last faltering word is to Ray, on the phone. She dies not long afterwards in her apartment.

• Back Street at the TCM Movie Database
• Back Street at IMDb  
• Back Street at AllMovie