The narrator insists he is sane but hears and sees things others do not. He cares for an old man with an "evil eye" but is driven mad by the eye. In a fit of madness, he kills the old man and hides his body. Though he believes he has committed the perfect crime, the beating of the old man's heart in his head overwhelms him until he confesses to the murder. Guilt is the overarching theme as it destroys both the narrator and his victim.