Here's a summary of the key events at the end:
* Draco Malfoy's betrayal: Draco, under pressure from Voldemort, attempts to kill Dumbledore, but fails. He is saved by Severus Snape, who then kills Dumbledore with the Killing Curse.
* Dumbledore's death: Dumbledore's death is a major turning point, leaving Harry and his friends devastated.
* Snape's true allegiance revealed: Snape becomes Headmaster of Hogwarts and reveals his true allegiance to the Death Eaters, shocking Harry and the others.
* Horcrux discovery: Harry and Dumbledore discover that Voldemort created six Horcruxes, and they successfully destroy one, the locket belonging to Salazar Slytherin.
* The prophecy: Dumbledore reveals a prophecy concerning Harry and Voldemort that predicts one of them will have to die to defeat the other.
* The search for Horcruxes: With Dumbledore gone, Harry and his friends must now find and destroy the remaining Horcruxes to defeat Voldemort.
The ending leaves the reader with a sense of despair and uncertainty. Harry's world has been turned upside down, and the fight against Voldemort becomes even more perilous.