 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.