In this chapter, we gain insight into Harry Potter's challenging life with the Dursleys, his neglectful and abusive relatives. Harry lives in a cupboard under the stairs in their home, and is often mistreated and belittled by his Uncle Vernon and Aunt Petunia, who favor their own son, Dudley. The chapter opens with a description of a typical day in the Dursley household, illustrating Harry's miserable existence, where he is forced to complete chores and endure Dudley's tantrums.

Dudley, a spoiled and overweight child, throws a fit when his birthday presents are fewer than expected, showcasing the Dursleys' neglect of Harry in comparison to their indulgence of Dudley. The contrasting treatment highlights the cruelty Harry faces daily, emphasizing his isolation and lack of love.

The family decides to take Dudley and a friend to the zoo for his birthday, and, surprisingly, Aunt Petunia allows Harry to join them. This rare outing offers Harry a glimpse of normalcy and excitement, as he is thrilled to visit the zoo, something he has never done before. During their visit, Harry is fascinated by the various animals, particularly a large boa constrictor in its enclosure. While at the snake exhibit, Dudley and his friend push Harry aside and attempt to get a closer look at the snake, which is uninterested in them.

In a moment of frustration, Harry talks to the snake, expressing his empathy for its confinement. To his astonishment, the snake responds, and they share a brief connection. Harry is filled with delight when the snake suddenly slithers to the front of the glass enclosure, tapping it with its tail, which catches the attention of the visitors. Just then, Dudley and his friend shove Harry again, causing him to lose his balance. In a bizarre turn of events, as Harry loses his grip, the glass of the enclosure vanishes completely, allowing the boa constrictor to escape.

The chaos that ensues frightens the zoo-goers, while Harry is left in shock at what has just happened. He feels a strange sense of freedom and exhilaration for the snake, who thanks him in its own way as it escapes. However, the incident causes a major uproar, and Uncle Vernon is furious upon their return home. He blames Harry for the incident, despite the fact that Harry himself is bewildered by his unintentional magical act. This leads to Harry being punished and locked in his cupboard, further highlighting the Dursleys' mistreatment and the negative consequences Harry faces for something he cannot understand.

This chapter effectively foreshadows Harry's magical abilities and sets the tone for his journey of self-discovery. It illustrates the stark contrast between Harry's mundane and harsh life with the Dursleys and the magical world that awaits him, establishing a sense of hope and anticipation for the reader as Harry's true identity begins to unfold.