This is a short little play which I have read elsewhere in Agatha's books. A patient has fallen from a balcony suffering physical injuries, but also psychological injury that paralyzes her & prevents her from speaking. The inspector investigating & the doctor treating her are working together with nurses & an assistant to perform an experiment using a machine to question her & assist in translating her answers. The members of her household are present to witness this experiment; they are a quarrelsome bunch prone to pointing fingers & blaming each other for her original "accident" & resulting condition. They consist of her husband (a philanderer short of cash), a wastrel brother (also short of cash), a jealous sister, the husband's young & beautiful secretary with whom he's suspected of having an affair, & the hired nurse caring for her (who is assisting the doctor). Each of them has reason to be nervous about what the patient will reveal about her accidental fall. This short play is concise & presents a clear picture & a lot of information in a brief space--a hallmark of Agatha's works. I enjoyed it.