During the final event of the Grand Magic Games, Gray is tasked with beating Rufus, which is the key to Sabertooth's fall. But it seems to be a one-sided battle as Rufus uses his Memory Magic to make new magic, as well as causing Gray to forget his own!
After reading the books, 
you're supposed to put 'em back!
!عليك أن تعيد الكتب إلى محلّها بعد أن تنتهي من قراءتها