In the short story Strange Jest, Uncle Mathew Stroud was the late great great uncle of two young people Charmian Stroud and Edward Rossiter. With no other relatives, he promised the two that when he died, he would split his fortune equally between them. However he was a shrewd and suspicious man. He did not trust banks, investments or lawyers as he knew people who have come to grief entrusting their money to these channels. So when he died, Charmian and Edward were left with the puzzle of how he had hidden his money away.
All they had to go on were various hints dropped by Uncle Mathew. They knew that Uncle Mathew had liquidated his securities and drew out large sums but nobody knew what he did with the money. While he was alive, he had said that the best thing to do was to convert money into bullion and bury it. He had also said that the best place for money was in a box under one's bed or buried in the garden. Finally there was the puzzling clue that just before he died, he had tapped his right eye and winked at Charmian and Edward.
Following the clues, Edward and Charmian had dug up the garden and ransacked the house but found nothing. For Miss Marple, however, it was necessary to first understand the man, or as Mrs Beaton put it, first catch your hare. She saw her Uncle Henry as a parallel of Uncle Mathew, a shrewd suspicious man who loved puns and jests. But mainly, Uncle Matthew had hidden the fortune well because he love Edward and Charmian and wanted to protect their legacy from thieves. As Miss Marple went on to show, Uncle Mathew had hidden his treasure so well that even when Edward and Charmian were holding it in their hands, they did not recognise it.