The story takes place in a house. There is a mother, father, son, and a sargent
In the story the paw has a spell on it to give three men wishes. So there was a wish that was for death and that wish went to the son.
Sargent Major is explaining the background of the monkey's paw. So basically he tells the family that an old fakir put a spell on it. He also said that he put a spell on it that 3 separate men could get three wishes from it.
Since the father has a some wishes left he uses one of them to try to make his son be alive again.
When the mother and father are talking they here a knock on the door. Once the mother hears that knock she thinks its her son
Before the mother gets a chance to open the door the father wishes that the son will be dead again. So once the mother opens the door there is nothing there