Answer:
The detail from the story that is part of the conclusion is death.
Step-by-step explanation:
When Morris tells Mr. White that the third wish the first man had was death, he reveals a small detail that is also part of the end of the story.
When Mr. White hears the knocking of the door in despair, knowing that whatever it was knocking on, it would not be his son, he quickly takes the paw and wishes that this being "disappears" or "dies", and so it can’t harm him and his wife.