Noted French research scientist Dr. Michel Touzac travels to Chicago for a medical convention, and once there, is convinced by his colleagues to go to Hinky Joe's, a nightclub, where the Great Joseph Targel, a sketch artist, is performing. Though he doesn't recognize her at first, Michel is surprised to discover that his wife Karin, whom he had left behind in France, is working as Targel's musical accompanist. Karin later attempts suicide, and Michel performs an experimental operation which saves her life. As Karin lays in bed, Michel browses through her diary, which prompts him to recall their first meeting in Paris, when Michel, a young intern, was called to the theater to tend to Karin's sprained ankle: After a brief courtship, Michel and Karin marry, and she gives up her career in the theater. A few years after the birth of their daughter Susette, the jealous Michel overhears two older women gossiping in a bakery, accusing the beautiful Karin of infidelity. Michel then follows Karin to the home of Uncle Robert, a blind gentleman, but before he can confront the two, he is diverted by a friend. After learning that Karin goes to Bob's every afternoon, Michel publicly accuses her at Susette's birthday party of adultery. Karin then strikes Michel and rushes upstairs, only to come down later that evening to discover that Michel has left and taken Susette with him. The diary ends with an entry stating that after months of searching for her daughter, Karin gave up hope and moved to America. As Karin begins her recovery from the suicide attempt, Michel has her moved to the Rossmore Resort, a private sanitarium in Wisconsin, where he tells her that Susette thinks that her mother is dead. Despite her hatred for Michel, Karin agrees to return home with him, where she is presented to the teenage Susette as Michel's "new" wife Florence. Susette rejects her new mother, however, having grown up idolizing the "dead" Karin so much that she had built a shrine to her. In an attempt to bring Karin and Susette together, Miss Tucker, the housekeeper, leaves the Touzac household, but her departure only drives another wedge between mother and daughter. Later, Targel visits the Touzacs and asks the unhappy Karin to return to the stage with him. During Susette's birthday party, Bob arrives and tells Karin that he and Michel became close friends after Michel learned that he was merely taking piano lessons from her. Bob also tells Karin that he later moved to America with Michel and Susette, where he regained his eyesight through an operation, and that Michel has never stopped loving her. Upon the conclusion of her birthday party, Susette asks Targel to draw a portrait of her mother, but upon hearing Karin speak of her mother, Susette becomes upset and threatens to leave home. Though still in love with Michel, Karin decides that it is best for all if she is the one to leave. As Michel tries to stop Karin, Susette overhears him call Karin by her real name and finally realizes that she is her real mother. Susette then stops Karin from leaving by calling out, "Mother, mother."