Harry Potter and the Dealthy Hallows is the seventh and final book in J.K. Rowlings Harry Potter series. Voldemort is continuing to accumulate power and it is up to Harry, Ron, and Hermoine to find the remaining Horcruxes to defeat him once and for all. When the Death Eaters descend upon Hogwarts, it leads to a battle that will affect the future of the wizarding world forever.
In the Great Hall, teachers and prefects are sneaking the younger students out of the school before the battle begins.
The Order and the professors have agreed upon a battle plan and start splitting up. Many students who are overage have stayed to fight, and they’re all preparing for the battle that will come soon. The air is tense with expectation, and Harry, who is starting to panic, still does not know where to begin looking for the diadem.
As he races through the hallways, he has an idea. Everyone keeps saying the diadem hasn’t been seen by anyone in living memory. That does not, however, include ghosts. He hunts down Nick, the Gryffindor ghost, and asks him about it. Nick points him towards the Grey Lady, who is Ravenclaw’s ghost, and Harry asks her about the diadem. She tells him that she was Ravenclaw’s own daughter, and that she was the one who stole the diadem from her mother.
Harry runs into Hagrid after talking with the Grey Lady, and suddenly he knows exactly where the diadem is. He realizes he saw it last year in the Room of Requirement, when he went in to hide his Potions book. It’s a tiara, on a stone bust, in that junky old room. He can’t believe it.
As he’s racing to the Room of Requirement he finally finds Ron and Hermione, who had the brilliant idea to go down into the Chamber of Secrets and get some basilisk fangs, which is one of the only other things that can destroy the Horcrux. He’s amazed at their brilliance. Hermione has already destroyed the cup.
The battle has begun and they race even harder to get there. When they finally get the Room of Requirement open, they begin searching for the stone bust on which that Harry knows the diadem sits. They’re disgusted to find out that Draco Malfoy, Crabbe, and Goyle are in the room as well.
They begin to duel and Harry just manages to grab the tiara before the piles of junk bury it forever. The room catches on fire from a spell and they manage to get out, saving Malfoy and Goyle in the process. Crabbe is burned to death by the Fiendfyre.
After they get out, they happily realize the tiara got destroyed in the magical fire, but suddenly Percy and Fred come into view, dueling with two Death Eaters in the hallway. Suddenly the wall is blasted open from the outside, and Fred is killed in the explosion.