The Librarians (The Librarians #3)

Hot on the trail of the sudden abduction of cult film director Sol Schick by his suddenly powerful assistant Orson Orville, the Librarians uncover the shocking secret behind the mystery they've been trying to uncover: In an alternate timeline where magic is used as a global weapon, a group of all-powerful wizards have set their eyes on our Earth - and the invasion is about to begin.