A cynical New York actress is courted by a naive young soldier from Texas on his way to war in France.
In April 1917 actress Daisy Heath (Margaret Sullavan) sleeps late and advises her maid Martha (Hattie McDaniel) against marriage. Daisy asks Sam Bailey (Walter Pidgeon) to fix her missing rehearsal. Private Bill Pettigrew (James Stewart) marches in the street. In the evening Bill is hit by Daisy's car and gets a ride with her. She snickers at his comparison of Texas with New York. Bill tells his army buddies that she was his date and gets a star photo of her. They go to the theater to meet her, and Daisy goes along with Bill, who walks her home. She gives him her phone number, and he says she is an angel. Daisy tells Sam that she is only a habit for him. They let in Bill, who brings her flowers and candy. Bill rubs her head, and she gives him her photo. Bill leaves with Sam and shows him how to roll a cigarette. Sam decides to give a show for the boys, and Daisy (Mary Martin) sings "Pack Up Your Troubles," joined by the soldiers. Bill invites Daisy to see the camp while Sam watches wrestling. Daisy says that Bill believes in love, living and dying. She gives him a kiss and agrees to show him the city. Daisy asks Sam not to go to war.
Bill and Daisy have fun at Coney Island. Daisy goes to a dinner date with Sam, but he is jealous. Daisy kisses him. Bill learns that they are shipping out, and he can't get a pass. Sam asks Daisy not to see Bill again, and she agrees. Bill finds Daisy at the theater. She misses her performance to go AWOL with Bill, who says he is in love with her. It rains, and Martha bakes Bill's boots. Bill tells Daisy they could get married. Sam finds Bill in her apartment. Sam and Daisy say they love each other, but Daisy says that they got it from Bill. Daisy wants to give Bill a dream to take and is afraid he will die if he learns about them. Bill says that Daisy should not be married to a cowboy. Daisy says that she will marry Bill, and Sam leaves but goes to their wedding. After the ceremony Bill joins his unit's trucks. Sam tells Daisy he is leaving. Bill and Daisy write to each other during the war. Martha receives a registered letter for Daisy. Sam visits Daisy at a nightclub, where she sings "Pack Up Your Troubles." Martha gives the letter to Sam, and Daisy cries over Bill's death.
This touching romance contrasts the sophistication of a liberated woman to the simpler values of an innocent soldier. His real emotion and admiration for her beauty helps to revive the tired affair Daisy is having with a producer. Her giving herself to Bill before he leaves represents a patriotic sacrifice for war.