The day before chemist Dr. Hans Wynhold leaves for a six months business trip to Africa, he meets chemistry student Christa Weiden. They spend the evening together in St. Pauli and fall in love. She doesn't tell him that she'll start the next day at the chemistry laboratory he works at too, because he says he doesn't like women in "men's jobs". Only after his departure the next day Christa learns about Hans' reputation as a Don Juan. In fear that she'll lose him to another woman, she follows him... and starts a series of complications.
 Hans Söhnker
Dr. Hans Winhold
 Elfie Mayerhofer
Christa Weiden
 Ursula Herking
Frl. Budensieck
 Maria Koppenhöfer
Mrs.Senator Petersen
 Lola Müthel
Isabella Brandt
 Fritz Odemar
Friedrich Weiden, Christls Vater
 Rudolf Schündler
Peter Ordner, der "Verlobte" Christls
 Ernst Waldow
Dr. Kurt Drews - Rechtsanwalt