This was a lot of fun, and will be hard for me to review for fear of spoilers.
Old Simeon Lee has called his family to him for Christmas. But not for merriment and goodwill toward men, but rather for insults and maliciousness. Then, Simeon ends up murdered rather gorily. The police and Poirot arrive on the scene, and what follows is another delightful Agatha Christie mystery in which family secrets are exposed and we--and the family--are left wondering how a man was murdered when the door was locked from the inside and the windows were shut.
I am definitely adding this to my list of annual rereads!