The faith of a little girl helps her pregnant sister in an orchestra while her husband is lost in the war.
Seven-year-old Mike (Margaret O'Brien) arrives in New York on a train and waits for her sister to pick her up. A policeman and others try to help her, and she finds her sister Barbara (June Allyson) playing in a concert and walks on stage as Jose Iturbe (himself) conducts. Iturbe is planning to fire Barbara, but Andrews (Jimmy Durante) tells him that several men and women have left the orchestra for military service. Barbara and her orchestra friends sneak Mike past Mrs. McGuff (Ethel Griffies) into the boardinghouse. Barbara has not received a letter from her husband in the Pacific for several weeks. She gets a letter, but it is the one telling her that Mike is coming on the train and to pick her up. Mike notices that others are concerned about Barbara and is worried that she is sick. Barbara faints, and the doctor (Harry Davenport) tells Mike the secret that she is going to have a baby. Mike shares the secret with her pregnant sister.
During a rehearsal the musicians improvise with jazz, and Andrews plays the piano and sings "Toscanini, Iturbe, and Me." While Iturbe plays a piano concerto, Mike carries a stool to Barbara so that she can sit down. As they are leaving for their tour, Mrs. McGuff gives Rosalind (Marsha Hunt) a telegram from the War Department for Barbara. Rosalind and the others decide not to tell Barbara. As they have dinner a harmonica player plays "Clair de Lune" for Barbara, who cries and leaves. When Rosalind finds Mike about to see the telegram that fell out of her purse, she pushes her away. Just then Barbara comes in and is shocked at what Rosalind did. Mike says she is all right, and Rosalind says she gets love letters too.
The orchestra plays for an audience of soldiers, and Andrews is thanked for making the arrangements. An officer is about to ask Iturbe to play, but Andrews thinks he means him and plays a rousing song in which all join in the singing. Andrews carries the sleeping Mike to bed and humorously tells Barbara that they are enemies. Mike likes to pray in church and advises Barbara to pray for her husband. Marie (Marie Wilson) has been saving for a fur coat but gives money to her alcoholic uncle Ferdinand (Hugh Herbert). She asks him to forge a letter from Barbara's husband and tells him to mail it from San Francisco. When they return, Mrs. McGuff gives a letter to Barbara, who reads that her husband was lost on an island for four months but survived on coconuts. Mrs. McGuff finds Mike hiding and invites her to stay. Mike and Barbara go to church to thank God. Ferdinand asks Marie for more money and tells her he could not write the letter. Rosalind and the others realize Barbara's husband is safe and are happy. Mike and Andrews wait for Barbara to have her baby, and the orchestra plays Handel's Messiah with the "Hallelujah" chorus.
This classical musical portrays the emotional challenges
of women during the war. The innocence of a little girl knows
that angels bring babies, that she is in touch with one, as is
the kind Andrews.