Mother Wolffen, a washerwoman, is a woman of principle: A poor man must do what he must to get through life, only he mustn't get caught doing it. All sorts of crooked deals contribute to the improvement of the daily menu and the increase of household funds. When everyone is searching for pensioner Krueger's missing beaverskin coat, Mother Wolffen and her family are calmly enjoying fresh roast venison.

The deceased owner of a medieval castle stipulated the following in his will: The heir to his mighty estate would be the elder of the two stepsisters, Katharina and Margrit von Kronberg, namely Margrit, if she married Heinz Wagner, a cousin who had just returned from captivity. When Margrit observed Katharina and Heinz rendezvousing at a nearby lake, Margrit demanded that her husband leave the castle immediately, before she, the elder sister, and Heinz were married. Furious, Katharina then plotted to poison Margrit. Only when Katharina dreamed that the village youth would avenge Margrit's violent death according to ancient tradition and that she, Katharina, would be burned on a pyre like witches in the Middle Ages, did she, after awakening from this nightmare, abandon her bloody plan. Her change of will is rewarded: Heinz has decided to marry Katharina and not Margrit.

Biographical movie about Julius Robert Mayer (1814-1878), a surgeon and town doctor in Heilbronn, who studied heat for many years and was the first to correctly formulate the basic principles of the theory of mechanical heat and the principle of conservation of energy. Competing Prussian scientists laugh at him, and his life is full of misunderstandings and persecution. The film tells of his fate and his long and futile struggle for recognition of the results of his scientific work.