Miss Marple tells the next mystery.
It is about her niece Mabel, who was married to Geoffrey Denman, a man who was unkind and violent. In the house there were two maids and Geoffrey’s invalid father. The man died one night, and the cause of his death was allegedly the consumption of some mushrooms. The two maids claim that the man talked a lot of gibberish about fish before he died. Now rumours are circulating about Mabel being responsible for her late husband’s death, especially since it is known that they quarrel a lot and she bought cyanide.
Miss Marple realized that the key of the mystery lay on the words Geoffrey last said. She thinks that some words spoken out of context might be understood in some other way. So questioning the maids, she discovers that the ‘heap of fish’ they had apparently heard was not literal, and what they failed to understand was ‘pilocarpine’, which they took it to mean ‘a pile of carp’. Miss Marple reads a book about poisons which explain that pilocarpine was used an antidote to atropine poisoning,. Atropine can be found in eyedrops, so she talks to the old Mr Denman, who suffered from bad vision, and he admits he added a few drops of atropine to the glass of water that his son always drank at night. He killed him because Geoffrey wanted to send him to an asylum. The man, who is shown signs of insanity, which runs in the family, is sent to a mental asylum in the end.
The last of this chapter is sweet as Raymond tells his aunt there is something she doesn’t know, and Miss Marple surprises him when she reveals she knows he has proposed to Joyce when they nipped to the garden for a bit.