In "Harry Potter and the Goblet of Fire," the fourth book in the Harry Potter series by J.K. Rowling, Harry returns to Hogwarts School of Witchcraft and Wizardry for his fourth year. The school hosts the Triwizard Tournament, a magical competition between three wizarding schools: Hogwarts, Beauxbatons, and Durmstrang. As the tournament unfolds, Harry is mysteriously entered as a fourth champion, despite being underage. He faces dangerous tasks and uncovers dark secrets, including the return of the dark wizard Lord Voldemort, setting the stage for future conflicts in the series.