Poirot gets a letter from a woman called Emily that wants to consult him because she believes her life is in danger. Poirot notices the letter was written a few months before he got it, and when he realises Emily is now dead Poirot decides to investigate.

I love Agatha Christie, but this is one of the few stories that stayed with me since the first time I read it. Maybe it was Bob the dog, maybe it was the reflection on the mirror that I got before Poirot. Anyway, it is a wonderful mystery that I will likely read again in the future.