“After Twenty Years” concludes with three surprises in quick succession. First, Bob realizes that the man who claims to be Jimmy is not Jimmy. Second, it is revealed that Bob is a well-known criminal. Third, Jimmy confesses in his note that he was the police officer to whom Bob spoke at the beginning of the story. All these surprises show different aspects of the changes wrought by time.

Either Jimmy or Bob or both of them have changed so much that Bob does not recognize Jimmy, despite the fact that he is expecting him. He then fails to realize that the second man he meets, who claims to be Jimmy, is not his old friend. It is only when they pass the brightly lit window of a drugstore that he notices a physical feature that does not change with age, the shape of a man’s nose. When he comments on this physical point, the detective responds with a moral one: time “sometimes changes a good man into a bad one.” This does not seem quite accurate as a summary of what has happened in the story. There is no indication that Bob was a particularly good man at the age of eighteen, when he last saw Jimmy. Bob’s own description suggests that they both had to work out what kind of men they were to be, though he is full of praise for Jimmy’s qualities as a true friend. It may be that Jimmy has come to care less about friendship, though it seems more likely that the qualities Bob saw in him would always have given him a strong sense of duty.

Although Bob thinks him slow, Jimmy is the more perceptive of the two. He recognizes Bob and also understands how his character has developed. He sees what has changed in Bob, as well as how he has remained the same. Bob, meanwhile, fails to recognize Jimmy as he is now, leaving it for the reader to decide whether Jimmy has changed so as to be unrecognizable or whether Bob never knew his friend as well as he thought.