Charles and Sophia meet abroad and become engaged, but when Charles meets Sophia again in England, she refuses to acknowledge their engagement until the mystery of her grandfather's murder is cleared up. Charles meets Sophia's family, her aunts and uncles, and her step-grandmother. Each member of the family is suspicious of the step-grandmother because she was fifty years younger than her husband. They all think she must have gotten tired of waiting for him to die so that she could inherit his wealth. But Charles isn't so sure, and Sophia is afraid that it might have been someone else in the family, someone close to her.

This was a really interesting murder mystery because all the characters are so different and vibrant. There are a lot of suspects, but they are all very memorable with lively personalities. Sophia's father is withdrawn and bitter, but her mother is a dramatic actress, always acting out a scene. Sophia's uncle is highly emotional with a quick temper, but her aunt is quiet and deliberate in all her behavior. Sophia's brother and sister are too young to really be involved, but they definitely notice all the weird goings-on about the house.

Charles has to consider what sort of person would be a murderer, and does he really want to marry into a family like that? He tries to help the police find some clues, but no one seems to have any motive for murdering the grandfather.

The plot has several twists, and I loved all the red herrings. As always, Agatha Christie's writing style is perfection. She really keeps you guessing!

I liked Charles, but I didn't really like Sophia that much. Next to everyone else, she is sort of a bland person. Most of her personality is just reacting to other people, trying to rein in the excessive behavior of her relatives. But she is a good judge of character and has a clear head. She describes her relatives to Charles with perfect clarity. For an engaged couple, they don't have much romance in the book. They are too busy tracking down the murderer.