The story is set in the drawing room of "Les Cerisiers" sanatorium, an idyllic home for the mentally ill, run by famed psychiatrist Mathilde von Zahnd. This drawing room connects to three rooms, each of which is inhabited by a mentally ill patient. These three men, all physicists by trade, are permitted use of the drawing room, where they are periodically monitored by the female nurses that are charged with their care. The first patient is Herbert Georg Beutler, and he believes that he is Sir Isaac Newton. The second patient is Ernst Heinrich Ernesti, who believes himself to be Albert Einstein. The third patient is Johann Wilhelm Möbius, and he believes that he is regularly visited by the biblical King Solomon. When the play begins, "Einstein" has just killed one of his nurses, and the police are examining the scene. It is revealed through their discussion that this is the second slaying of a nurse by one of these three patients in just three months, the first having been committed by "Newton".