A piano virtuoso has a child out of wedlock to her fiance, who is killed trying to save her life. Their son is brought up by foster parents and becomes a musician.
"In 1917, Carlo Salvini (George F. Houston), an opera singer and captain in the Italian army, returns home to participate in a performance of Carmen for a Red Cross benefit. Afterward, Carlo meets Franceska Manzoni (Helen Westley) and her niece, pianist Ann Prescott (Josephine Hutchinson). When German troops move closer to the village, Carlo and his fellow soldiers help Franceska, Ann and the other villagers evacuate. Before Carlo can get away, however, the German troops invade and Ann hides him in the attic. During the ensuing months, Ann and Carlo fall in love and marry. Carlo returns to the front line, and later Ann gives birth to their son, whom she names Carlo. Then, Franceska, who was her piano instructor too, dies, and her final wish is for Ann to dedicate young Carlo's life to music. In order to save her baby from the enemy concentration camp, Ann turns him over to the custody of a Dominican convent.
After Ann learns that Carlo has died, she returns to the convent, but the Mother Superior (Laura Hope Crews) informs her she cannot have custody of Carlo without a husband. Desperate, Ann decides to enter the convent as a nun, and is able to ascertain which child is her own. Ann is forced to leave the order, however, when she is caught trying to leave with the baby.
Ann returns to her family villa, immerses herself in the piano, and becomes an acclaimed concert pianist. Years later, after hiring an agency to track her son, Ann learns that Carlo was adopted by diplomat Marco Turina (John Halliday) and his wife Sylvia (Mona Barrie). A friend, Groce (Walter Kingsford), helps Ann get invited to a party at the Turina home, and there Ann sees Carlo, who is now called Guido Turina (David Scott) and is a young college student. A bond between Guido and Ann develops, and he confides to her that he feels a strange calling to become a musician, although his father plans for him to follow the long line of Turina men and become a diplomat. In order for Ann to continue to see Guido and coerce Marco to allow the boy to sing, she develops a friendship with Marco, but Sylvia misconstrues the relationship, and a desperate Ann is forced to confront her. Ann reveals Guido's parentage to Sylvia so that Sylvia will help the young man fulfill his true destiny. Ann agrees to leave, but receives her life's wish when Guido becomes an opera star."
Edward Small bought the rights to the novel in November 1934. Lillian Hellman wrote an early draft of the script. Philip Dunne was then hired to work on it with Ralph Block.
According to Dunne "The Melody Lingers On lingered not at all in theaters but died a swift and merciful death".