Prospero's Daugther, book 3: Prospero Regained
L. Jagi Lamplighter2011

Prospero, the sorcerer on whose island of exile William Shakespeare set his play, The Tempest, has endured these past many centuries. His daughter Miranda runs the family business, Prospero, Inc. so smoothly that the vast majority of humanity has no idea that the Prosperos' magic has protected Earth from numerous disasters. But Prospero himself has been kidnapped by demons from Hell, and Miranda, aided by her siblings, has followed her father into Hell to save him from a certain doom at the hands of vengeful demons. Time is running out for Miranda, and for the great magician himself. Their battle against the most terrifying forces of the Pit is a great fantasy adventure.