O. Henry has written a moralistic story in which he contrasts the lives of criminals and law-abiding citizens. The members of the underworld may seem smarter if they make a lot of money and avoid getting caught, but in the long run it is the honest, industrious people who enjoy the better lives. "Silky" Bob has apparently made a lot of money in his life of crime, and yet he seems like a lonely man. People like him have to keep on the run. They have no roots. They make a lot of enemies but not very many friends. He tells the uniformed officer whom he doesn't recognize as his old friend Jimmy Wells:
"You see, the West is a pretty big proposition, and I kept hustling around over it pretty lively."
As he approaches middle-age, Bob is a wanted man in danger of going to prison. Jimmy, by contrast, has a wife, a family, a home, a steady and respectable job, and peace of mind. O. Henry's story resembles Aesop's fable about "The Tortoise and the Hare," in which the tortoise wins their race because he is "slow and steady." When Bob is told that he is under arrest and being sent back to Chicago for questioning, he may suddenly realize that he has chosen the wrong way of life and that it is probably too late for him to do anything about it.
Bob and Jimmy represent two types of men--those who want to live in luxury without working and those who are do the world's work and uphold civilization. Jimmy felt compelled to have his old friend arrested because he was an honest citizen who believed in law and order. Bob and Jimmy may have been good friends twenty years ago, but they would not have remained friends if Bob had stayed in New York and continued to follow a life of crime and indulgence. They are not really friends anymore. They are actually erstwhile friends--that is, men whose relationship is based on the fact that they used to be friends. Their friendship was deteriorating even though they never even saw each other during those twenty long years.
We feel some sympathy for "Silky" Bob because so much of the story is told from his point of view. We think he came to New York to see Jimmy, but he may have come there because he knew the police were looking for him in Chicago. At the same time, we cannot fault Jimmy for having him arrested by the other officer. O. Henry has mitigated the severity of Jimmy's betrayal in several ways. For one thing, the arrest is made politely. Bob and the plain clothes man are actually walking arm in arm. It seems possible that Bob will get off rather lightly. The arresting officer tells him:
"Chicago thinks you may have dropped over our way and wires us she wants to have a chat with you. Going quietly, are You? That's sensible."
Bob is wanted for questioning. He has not been charged with any crime. He is a smooth talker and may be able to talk his way out of whatever jam he is in. He has money too; he can afford to hire a good lawyer.
The mood in “After Twenty Years” is ironic, reflective and wistful.
Mood is the emotion of a story.
This story is about two friends who agree to meet in twenty years. They both keep their date, but one turns out to be a criminal and one turns out to be a cop. The cop has to decide whether or not to turn his friend in. He finally decides he has to do something, so he gets another cop to arrest his friend and sends him a note.
The mood is reflective, and remembering.
"Twenty years ago to-night," said the man, "I dined here at 'Big Joe' Brady's with Jimmy Wells, my best chum, and the finest chap in the world.
It is also somewhat wistful, because things do not always stay the same. People change. We cannot control the change, but we sometimes have mixed feelings about it.
Finally, there is a high note of irony in the fact that one person became a cop and another a crook.
Well, well, well! --twenty years is a long time. The old gone, Bob; I wish it had lasted, so we could have had another dinner there.
Ironically, the cop has to decide whether he wants to be a good cop or a good friend. Will he honor his old friend’s memory, or do his duty? He decides he has to turn him in, but he can’t do it himself.