APRIL: The Jewel Robbery at the Grand Metropolitan
No references. Mrs. Opalsen’s pearls are said to have been used in 1908 (in an actual clip from Oscar Wilde’s “Salome”), but there's no mention of how much time has elapsed.
MAY: The Adventure of the Egyptian Tomb
Poirot’s newspaper in the beginning of the episode reads June 1934 (possibly 1936). Hasting’s newspaper in New York reads January 1934 (possibly 1936). So the episode contradicts itself. Therefore, I choose to place it in early spring 1934, ignoring the references.
