A story spanning three generations, from 1871 to 1945. When Gustav Wengler, a farmer’s son, returns from the Franco-German war in 1871, he goes to work for a precision mechanics and optical company, where he soon becomes a master craftsman. Wengler loyally promises the owner on his deathbed that his sons and grandsons will also stand by the company.
In his daydreams, 15-year old Otto is a real hero who masters dangerous situations by the dozen. But in reality, the rather imaginative ninth grader has trouble moving up to the next grade. Fortunately, his teacher Nickel notices that Otto does not lack intelligence, but the ability to use his imagination for the requirements of everyday school life. Together with school director Menschke, Nickel tries to change Otto’s attitude. Although this is easier said than done, Otto eventually realizes that he has to try to build his cloud-castles only after school has ended. And his teacher is going to support him in his attempts.