A group of young American women/flappers arrives at the Hotel Venitien on the French Riviera. In the hotel lobby, Sally Baxter encounters Monsieur de Segurola, "the famous baritone", and asks him to write something in her autograph album. However, when she reads what he has written, she tears it out. Next, she spots handsome Andre Briault, "the famous tennis champion", and his girlfriend Simone. After Andre drives away, Sally notices Simone and de Sugorola making eye contact. (Albine, Andre's valet, does not approve of Simone either.)
When Andre later telephones Simone, he hears someone singing; Simone claims it is only a phonograph record playing, but then de Sugorola coughs. Andre heads over to the hotel to check up on her. She tries to distract him, but Andre spots de Sugorola trying to sneak out of her suite, tosses him out into the hall and breaks up with Simone.
The last part is witnessed by Sally. She chases after Andre to get his autograph, but her pen seems to be out of ink. After he leaves, she finds that there is ink after all; unable to get a taxi, she steals a car and follows him to the casino. There, she inadvertently loses 50,000 francs playing baccarat against him, and is asked to pay. She writes on a check that she has no money to speak of, and Andre good-naturedly tears it up.
Then Andre spots Simone. He is still in love with her, so Sally suggests he pretend to be in love with someone else. He thinks that is an excellent plan; he chooses Sally, telling her that this is how she can pay her gambling debt. He instructs Sally to never let him be alone with Simone and to not let him weaken. When Simone tries to win him back, he introduces her to his "fiancée", Sally.
However, he keeps falling for Simone's enticements. But Sally is extremely persistent, going to outlandish lengths to keep him out of her rival's clutches. Finally, she socks him in the jaw to stop him from chasing after Simone. He reacts by pushing her clear into the next room, knocking her unconscious. This finally makes him realize whom he truly loves.