In the summer of 1913, 17-year-old Jacob Petersen, a professor's son, feels disturbed by his awakening sexuality. He is fascinated by works of art depicting nude women, but feeling painfully inexperienced, he avoids contact with the opposite sex, although the family maid, Sophie, is willing to initiate him into lovemaking. Jacob is invited to spend his summer holiday at his uncle's cottage in the country, and he falls in love with his beautiful cousin, Vibeke. One night when Jacob's uncle is away from home, and Vibeke's mother goes to join a family friend, Dr. Mogensen, for a rendezvous, Jacob clumsily makes love to Vibeke. After a brief period of happiness, Jacob and Vibeke are forced to separate when she returns to college. He soon embarks on an adventure with his uncle's good-natured maid, Hansigne, who takes his sexual instruction a step further. This affair comes to an abrupt conclusion when Hansigne's lover catches them in bed, and a fight ensues. However, Jacob finds his uncle's middle-aged housekeeper, Miss Rosegod, to be receptive to his attentions. By now Jacob is fully confident of his charms, and on his train trip home, he seduces an attractive fellow passenger. Sophie is waiting to greet him when he arrives at his father's home.