What is the main conflict in Casting the Runes, and Other Ghost Stories by M. R. James?

In the short story, "The Experiment," a woman and her son get what they deserve when they kill the Squire Francis Bowles in order to get their inheritance. However, they are stuck when they realize they do not know where their money is hidden. By a clever trick, they end up raising the squire, but his only goal is to expose their treachery. To escape him, they must confess to their crime and are revealed as murderers.