In the short story "The Tell-Tale Heart" by Edgar Allan Poe, the theme which is the most obvious is the theme of guilt or innocence. If you remember that theme is the lesson about life that the author is trying to teach the reader, the narrator is both insane and guilty. The narrator denies the insanity and admits his guilt in the killing of the old man. Yet underneath the obvious theme is the theme or idea that humans have a terrible time dealing with guilt as shown in the narrator's nervousness especially when the police come to the house. Only the narrator hears the beating of the old man's heart which leads him to finally confess to the police as he cannot continue to hide his guilt.