I recently read the final book of the series. At one point was the vault heist, where the goblin Griphook runs off with the Sword of Gryffindor. Yet near the end of the book, Neville Longbottom suddenly has the sword and uses it to defeat the snake Nagini.
How could this be possible? Griphook wanted the sword because it was goblin-made, so I doubt he would given it over to any non-goblin. How does Neville suddenly get the sword?