Another devilishly complex mystery for the great Hercule Poirot…Returning after lunch, Hercule Poirot finds an enraged woman waiting for him outside his house. She demands to know why Poirot sent her a letter accusing her of the murder of Barnabas Pandy, a man she has neither heard of nor seen before. The strange thing is that the famous detective does not know him either, and he never sent the letter he is accused of. Entering his house, another visitor awaits him – a man who also claims to have received a similar letter from him, and Poirot begins to wonder how many more such letters have been sent in his name. The solution to the mystery lies in the details, and Hercule Poirot's gray cells seek the motives behind this case…Who sent the letters and why? Who is Barnabas Pandy? Is he really dead, and if so, was he murdered?