The short story involves Mr. and Mrs. White and their adult son, Herbert. Sergeant-Major Morris, a friend who served with the British Army in India, introduces them to a mummified monkey's paw. An old fakir placed a spell on the paw, so that it would grant three wishes. The wishes are granted but always with hellish consequences as punishment for tampering with fate. Morris, having had a horrific experience using the paw, throws the monkey's paw into the fire but Mr. White retrieves it. Before leaving, Morris warns Mr. White that if he does use the paw, then it will be on his own head.

At Herbert's suggestion, Mr. White flippantly wishes for £200, which will enable him to make the final mortgage payment for his house, even though he believes he has everything he wants. The next day his son Herbert leaves for work at a local factory. Later that day, word comes to the White home that Herbert has been killed in a terrible machinery accident. Although the employer denies responsibility for the incident, the firm has decided to make a goodwill payment to the family of the deceased. The payment, of £200, exactly matches the amount Herbert suggested his father should wish for.

Ten days after their son's death and a week after the funeral, Mrs. White, almost mad with grief, asks her husband to use the paw to wish Herbert back to life. Reluctantly, he does so. Shortly afterward there is a knock at the door. As Mrs. White fumbles at the locks in an attempt to open the door, Mr. White, who had to identify his son's mutilated body, and who knows the corpse has been buried for more than a week, realizes that the thing outside is not the son he knew and loved, and makes his third wish.

The knocking suddenly stops. Mrs. White opens the door to find no one is there.