In "Order of the Phoenix," the fifth book in the Harry Potter series by J.K. Rowling, the story follows Harry Potter during his fifth year at Hogwarts School of Witchcraft and Wizardry. As the threat of Lord Voldemort returns, the Ministry of Magic refuses to acknowledge it, leading to increased tension and danger for Harry and his friends. To combat the rising darkness, Harry joins a secret group called the Order of the Phoenix, formed by Dumbledore to fight against Voldemort and his followers, the Death Eaters. Throughout the year, Harry faces challenges, including a new oppressive teacher, Dolores Umbridge, and the struggle to unite the wizarding community.