The Green Door is the story of a young man who is always ready to pursue anything that might lead to adventure, who notices a trivial but odd incident and cannot rest until he finds out what it means. There's less wordplay, less outright comedy, but it's still O. Henry all over. The descriptions of a busy city at night reflect his taste for observing and capturing the colorful panorama of human nature and life in general. And of course, there's the ending. The interesting thing about this story is that the twist doesn't wait all the way until the last line; the moment with the most punch comes a little bit earlier.