A clever, sly fantasy with immediate intrigue and plenty of science. Henry begins in England, crushed and wobbly over his parents’ impending breakup. Pyrgus begins in the Realm of Faerie, trying to save a cage of kittens from being boiled in glue. Soon Pyrgus’s life is threatened and he is “translated” into the Analogue World, where he meets Henry. Various sorcerers, slimy businessmen, and a demon prince from Hael are all after Pyrgus’s life. Henry, Henry’s elderly oddball friend with mysterious scientific brilliance, and Pyrgus’s fiercely loyal sister, Blue, help Pyrgus return home and defeat the forces of darkness. Twists and turns provide real surprises along the way; touches of gore are occasional but vivid. The portals between worlds and the overlapping of science with religion may owe a debt to Philip Pullman, but they are welcome here as well. Aside from unjustifiably archaic gender roles, this is the perfect choice for Harry Potter fans who don’t know what to read next. (Fiction. 10-14)