The night before chemist Dr. Hans Wynhold embarks on a six-month business trip to Africa, he crosses paths with chemistry student Christa Weiden. The two spend the evening together in St. Pauli and develop feelings for each other. Christa decides not to reveal that she will be starting work at the same laboratory as Hans the next day, as he mentions not being fond of women in male-dominated professions. Upon his departure, Christa discovers Hans' reputation as a ladies' man and fears losing him to someone else. She decides to follow him, setting off a chain of complications.