As Hercule Poirot sifts through his post one particular morning, he alights upon a letter from an elderly and (as it transpires), exceedingly rich spinster - Miss Emily Arundell. She is clearly in great distress and seeking his help, but doesn't say why. Her only specific mention is 'the incident of the dog's ball'.
Memories define us. So what if you lost yours every time you went to sleep? Your name, your identity, your past, even the people you love - all forgotten overnight. And the one person you trust may only be telling you half the story. Welcome to Christine's life.