Author's Note: Some Half-Blood Prince spoilers. And J.K. Rowling owns most this, only the plot's mine.
A Glimpse at the Truth
Only two weeks of the Golden Trio's sixth year had gone by, and all of them were glad to return to the Hogwarts routine: feasts, Ron consuming them as if the world would end at any moment, helping lost first years find their way into classrooms, and Hermione scolding her two best friends for not paying attention in class.
Of course, changes had been made. For instance, Professor Snape teaching Defense Against the Dark Arts, to pretty much everybody's dismay; Horace Slughorn coming back to his old Potions Master position; Harry actually succeeding in said class; and there was the unavoidable worry and paranoia that Lord Voldemort could attack whenever he pleased.
It was researching some spells that Harry could find very useful if he had the, quite probable, misfortune of facing the Dark Lord once again, what the brightest witch of her age had been doing when Madame Pince saw her last.
No one recalled seeing her at dinner. Harry and Ron thought she was still in the library, and decided to go looking for her after eating. As they entered Hermione's sanctuary, several unusual things caught their attention.
The fierce librarian was missing from her spot, and she should have been closing the book room by that time; the lights were off, no candles or torches illuminating the desks and shelves; but the most chilling aspect of the room was the eerie silence floating in the dark environment, knitting webs of fear inside the two young men's heads.
None of them seemed, or wanted, to believe what their exhaustive search of the library and then, practically the entire castle and grounds, was screaming at them:
Hermione was gone.