An anonymous narrator announces that his real name shall remain a mystery, for he wishes to preserve the purity of the page before him. Instead, the narrator asks that we know him as “William Wilson” throughout the tale of misery and crime that he is about to tell. He explains that this tale will explain his sudden and complete turn to evil.

The narrator believes that he has inherited an excitable temperament from his otherwise dull-minded parents. As a young student, he escapes from this environment, and his early memories concern a large Elizabethan house in England where he attended school. He describes the school as a Gothic prison, with a spiked iron gate that has creaky hinges. The principal, who also acts as the pastor of the church, enforces the severe rules of the school. 

Despite the severity of his surroundings, the narrator emerges as a confident student and feels superior to his classmates, with the exception of one student. According to the narrator, this student bears the same name: William Wilson. This second William Wilson interferes with the narrator’s mastery over his classmates, thereby becoming for the narrator an object of fear and competition. This rivalry becomes more pronounced for the narrator when he learns that they joined the school on the same day and that, because of the two William Wilsons’ identical builds and styles of dress, many older students believe they are brothers. The narrator’s rival even imitates his mode of speaking, except he can never raise his voice above a whisper. Nevertheless, the narrator rejects any connection between him and his rival. Despite this antagonism, though, the narrator remains on speaking terms with his competitor and admits, at first, to being unable to hate him.