A fairly mediocre Agatha Christie, even though the author herself said it was one of her favorites. It starts well: a convicted murderer is found innocent, a year or so after he has died in prison. His innocence means that another family member is responsible for the death of Mrs. Argyle, a woman who had adopted five children.
There are a lot of psychological portrayals in this book, especially among the adopted children (all adults when the book takes place), but I don't think Christie quite nails it. She is best, I think, in a more light-hearted mode, or as light-hearted as murder mysteries can get (I guess they can get pretty light-hearted). The sinister tone of this book and the psychological complexity makes me wonder what someone like Ruth Rendell might do with the same plot.