Act One

The show may open with an optional curtain speech. In the speech, a cast member briefly describes the period of the show, the 1920s. The actor assures the audience that the era roared as loudly in England and along the Riviera as it did in America. The announcer then introduces the band, the Bearcats.

We open in Madame Dubonnet's Finishing School outside of Nice, France. The girls, all in their late teens, enter in a tizzy. They are scolded by Hortense, the chic French maid at the school, and reminded of their noblewomen-like expectations ("Perfect Young Ladies"). Enter the demure Polly Browne, announcing that her secret escort for the costume ball that evening will arrive at any moment. She plans on attending the dance in costume as Pierrette, and, in anticipation of the festivities, the girls reflect on the essential element for their exciting night ahead: the boy friend ("The Boy Friend").

Headmistress Mme. Dubonnet appears. The girls disperse, but she asks to speak with Polly. After a bit of cross-examination, Polly admits that she has no date for the dance; her wealthy father forbids her to have a boy friend, and young men who show interest in her might only be after their family fortune. Mme. Dubonnet assures Polly that she will speak with Mr. Browne as soon as he arrives for the ball.

Maisie, Polly's vivacious classmate, interrupts. After Mme. Dubonnet leaves, the dapper playboy, Bobby Van Husen, appears at the French windows and, although Maisie tries to shoo him away, he begs her to promise him every dance at the ball ("Won't You Charleston with Me?"). As they leave, Percival Browne, a pompous older gentleman — and Polly's father — arrives to see Mme. Dubonnet. As she enters, she is startled. It is a sudden moment of recognition. They begin by discussing Polly, but Mme. Dubonnet suggests that they have met before. She asks Percival if he remembers her, but he insists that he does not ("Fancy Forgetting"). The romantic tension is obvious to most. 

Polly comes in just as Tony, a messenger boy, delivers a package intended for her. Their attraction to one another is instantaneous, and she invites him to escort her to the carnival ball as Pierrot. They dance. Tony professes that he could be happy with Polly if only she could be happy with a lowly messenger boy ("I Could Be Happy with You"). They plan to meet at the bandstand on the beach later that afternoon. Tony leaves as Polly realizes that she doesn't even know his name. 

Percival enters and sees Polly; he notices her joy and happiness, and she secretly reveals to all of the girls that her "boy friend" has, indeed, arrived ("The Boy Friend – Reprise").

Act Two

That same afternoon at the shore, everyone is in beach attire, having a lovely time ("Sur Le Plage"). Lord Brockhurst, complete with monocle and high blood pressure, enters, flirting with the bathing beauties, but Lady Brockhurst is close behind. They discuss the mysterious disappearance of their son, Tony, from his college at Oxford. Lord Brockhurst continues eyeing the young girls in their bathing costumes.



Elsewhere, Polly and Tony meet up as planned. She denies being an heiress to a fortune, claiming to be a lowly secretary at the school. They joyously share their enthusiasm for the simple life ("A Room in Bloomsbury"). They are on the verge of a kiss as Hortense comes in. She is horrified. Polly convinces Hortense to keep their secret from Mme. Dubonnet, and the couple run off as the other young bathers arrive en masse, teasing Hortense. 



Lord Brockhurst spots Mme. Dubonnet with Percival Browne, and Brockhurst is smitten with the lady. She leaves to find Percival a bathing suit, and Brockhurst questions Browne about her. Percival resents the intrusion, though. Lady Brockhurst arrives again and whisks her husband away as Mme. Dubonnet comes back with bathing trunks in hand. Percival doesn't want to put them on, and Mme. Dubonnet bemoans him being a bad sport ("You Don't Want to Play with Me Blues").

All of the boys are focused on the coquettish Maisie, begging her to promise them a dance at the ball. She flirts with all of them, to Bobby's frustration ("Safety in Numbers"). Tony and Polly enter and arrange to meet at the cafe at nine before the ball ("I Could Be Happy with You"). They kiss as the Brockhursts enter and spot their son, Tony. He runs off as the Brockhursts call for a gendarme. In the confusion, everyone believes that Tony is a thief — including Polly. She fears that this means he was a gold digger all along.

Act Three

On the terrace of the cafe, couples are dancing. Mme. Dubonnet and Percival discuss Polly and realize that she is indeed in love and in need of a confidante. They recall their Armistice Day rendezvous. Bobby proposes to Maisie, and she promises to give him an answer at midnight; the other girls accept similar proposals from Alphonse, Marcel and Pierre. They agree to give their beaux answers at midnight, as well. The boys are frustrated by having to wait ("The Riviera").

Tony enters, and Hortense buttonholes him. She reports that Polly is broken-hearted. He enlists Hortense to urge Polly to attend the ball and he leaves to change into his costume. Lord Brockhurst, meanwhile, flirts with Dulcie. She says that he is too old to be flirting with her, but he protests, citing the advantages of loving a mature man of the world ("It's Never Too Late to Fall in Love").

Suddenly, a forlorn Polly, costumed as Pierrette, appears. Lady Brockhurst recognizes Polly as the girl with Tony and, upon seeing Polly in her costume, Mme. Dubonnet recalls a song that she knew as a child and sings it for Polly to cheer her up ("Poor Little Pierrette"). Tony, costumed and masked as Pierrot, arrives and approaches Polly, asking for the next dance. She is unsure, but his kiss assures her that this is her Tony.

The Brockhursts embrace their son. Tony and Polly admit to each other they have been flying under false colors. He confesses that he is the heir to the Brockhurst fortune, and she admits that she is the daughter of the millionaire, Percival Browne. Percival Browne then announces that Mme. Dubonnet has agreed to become his wife. It's suddenly midnight, and the boys await their fate. It's a unanimous yes! They all dance and sing ("The Boy Friend / A Room in Bloomsbury – Reprise").