While vacationing in San Francisco, Nick Charles receives an urgent, cryptic note from Maeve d'Avenant, a wealthy socialite widow whose brother's name Nick cleared years ago: "Mr. Charles, they mean to marry me. Please come at once." Nick wants to slip away to the luxury Grand Imperial Hotel to investigate quietly, but Nora stubbornly insists on coming along for "some fun." Annoyed by her refusal to let him work alone, Nick decides to play a joke on her at the hotel lobby. When the staff mistakes them for strangers, Nick pretends Nora is just a beautiful, fast-moving girl named "Miss Lettie Finhaden" whom he has just picked up.