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.
Before Harry can even wonder what Snape just gave him, he hears Voldemort’s voice magically magnified. He calls for his forces to retreat, and tells Harry that he has one hour to surrender. If he doesn’t, Lord Voldemort will enter the battle himself, and kill every single person in Hogwarts.
They make their way back up to the castle to think of what to do. All the casualties have been put in the Great Hall, and Harry is horrified to see how many have lost their lives. He knew of Fred's passing, but he’s shocked to see both Tonks and Lupin there, laid out side by side.
Harry can’t breathe seeing everyone who died for him, and he races to Dumbledore’s office. His sadness is too much to handle. He decides to look at Snape’s memory to see what he’d been trying to tell him.
What he sees is so shocking that he doesn’t even know how to comprehend it. Snape, it turns out, had been in love with his mother, Lily, since he was a boy. He worshiped her, and even though he lost her to James, Harry’s father, he never stopped caring about her. While Harry was at Hogwarts Snape did whatever he could to protect him, and it was all done out of love for his mother.
Harry also sees that last year, after Dumbledore took the ring Horcrux that shriveled his arm, he had a limited amount of time to live in spite of Snape’s best efforts to remove the poison. Dumbledore knew that Malfoy had been put to the task of killing him, and asked Snape if he would do it when the time came, since he was dying anyway. Events and memories unfold, and Harry sees that Snape was loyal, that he always was, and that perhaps he evencared for Harry in spite of his best efforts to hide it.
Harry also finds out that a piece of Voldemort’s soul is inside him, and has been since Voldemort tried to kill him as an infant. He must die in order for Voldemort to be truly defeated, and Voldemort has to be the one to do it.