High-spirited young Ossi Oswalda is the bane of her uncle and governess' existence. She insists on playing poker and smoking and talks with strange men on the street. When her uncle leaves to take up a new job, she looks forward to enjoying new freedom. Her hopes are dashed when her new guardian Dr. Kersten proves to be strict and unyielding. Frustrated with her cloistered life, Ossi sneaks out on the town dressed as a young man. She finds that being a man has its own disadvantages when she discovers she is not given the same gentle treatment when she is masquerading as a male.