Believing Black is out to kill him, Harry must navigate his third year at Hogwarts School of Witchcraft and Wizardry while also uncovering the truth about Black's past and his connection to Harry's parents. With the help of his best friends Ron Weasley (Rupert Grint) and Hermione Granger (Emma Watson), Harry learns more about the Patronus Charm and confronts the soul-sucking dementors that are terrorizing the school.