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.
Harry is devastated by the loss of his wand, and has no idea how he’s supposed to defeat Voldemort now that his special wand is destroyed.
He finds out from Hermione, however, that the thief that Voldemort keeps seeing, the man who stole something from him so many years ago, is none other than a very young Gellert Grindelwald. He also finds out that Dumbledore was very good friends with Grindewald. Grindewald, Harry knows, was the most famous Dark Wizard of all time until Voldemort emerged on the scene. Grindewald was all in favour of wizards dominating over Muggles, and Harry is shocked to find out that, at least when he was younger, Dumbledore agreed with him. Dumbledore had said everything they were doing was "for the greater good", and that later became Grindelwald's slogan. They dueled famously later in life, but Harry can’t stop thinking about how little he truly knew Albus Dumbledore. This new information leaves him feeling hollow and spent, and he wonders if Dumbledore ever truly cared about him at all.