Returning home after lunch one day, Poirot finds an angry woman waiting outside his front door. She demands to know why Poirot has sent her a letter accusing her of the murder of Barnabas Pandy, a man she has neither heard of nor ever met. Poirot has also never heard of a Barnabas Pandy, and has accused nobody of murder. He wonders how many more letters of this sort have been sent in his name. Who sent them, and why? Poirot returns in a stylish, diabolically clever mystery set in 1930s London.