In the second book of Rowling's wizard series, the courageous Harry Potter faces prejudice. After enduring another dreadful summer with the Dursleys, his guardians, twelve-year-old Harry returns to Hogwarts School of Witchcraft and Wizardry. He longs to play Quidditch, enhance his magical abilities, and cherish his friendships. However, these ordinary pursuits are soon eclipsed by ominous occurrences. Before the term starts, a house elf named Dobby warns Harry against returning to Hogwarts and disrupts his efforts to do so.

At Hogwarts, some students face emotional persecution from spiteful classmates for lacking pure wizard lineage. These students, derogatorily referred to as "mudbloods," are petrified by rumors of a monster lurking beneath the school in a hidden chamber. This recalls the chambers Harry encountered in Harry Potter and the Philosopher's/Sorcerer's Stone. Only the heir of Salazar Slytherin, one of Hogwarts' founders, can unlock this chamber to unleash the terrifying beast within. As Harry attempts to unravel the mystery, he is suspected of being the heir due to his ability to speak Parseltongue, the snake language, just like Slytherin could a millennium ago.

Misunderstood and worried about his best friends Ron Weasley and Hermione Granger, as well as his classmates, including Ron's younger sister Ginny who is trapped in the chamber, Harry strives to protect Hogwarts from ruin despite unjust accusations about his intentions and character. He confronts his nemesis, Lord Voldemort, while grappling with questions about his own identity and lineage. Bolstered by his self-confidence and trust in his friends, Harry's magical prowess grows stronger, enabling him to defeat his adversaries, including the menacing Voldemort and his own perplexing doubts.