Educational film about the symptoms, treatment, and prevention of tuberculosis. Mr van den Heuvel, a cobbler, lives with his wife and two small children in a one-room hovel in a dingy alley. He wants to work, but is usually too tired and is continuously coughing. He ignores the advice of his doctor to go to a health centre. His little daughter, Annetje, is not well either. At school she is listless, never wanting to play with her classmates. A visiting school doctor examines the girl and gives her a note for her parents, advising them to consult their doctor. Father considers this as nonsense.