Black Key's

Your in a library, looking for books for a project; of what you don't know, but you know that you need to find them. You moves some books, only for some to fall onto your head, making you fall to the ground. You get up, a little disoriented from the heavy books hitting your head. After you get your bearings, you look at the ground to the books that had nearly killed you and notice that they were a little odd, had keys attached to the cover, each with the same book design, but different keys. There were 4 of them, you decided to go collect them and the books you were after and purchased them. You get home and stare at the 4 books, nothing about them makes sense. They don't exist, all you know is that they tell history; and your gut tells you that it is untold and powerful.