In this third of the Gatekeepers series, Horowitz ups the ante considerably when he brings the third and fourth of “The Five” into the story. Identical twins Scott and Jamie, abandoned in a cave sacred to the Washoe Indians, have bounced from foster home to institution and are headed for much, much worse. A preemptive strike by the evil Nightrise Corporation makes Scott a captive and leaves Jamie, the less effective of the mind-reading twins, to make the rescue. Time travel, visits to a dream universe and mind control add a fascinating occult element to this thriller. Horowitz truly knows his way around a plot; he keeps the tension at a nail-biting level throughout and makes the apocalyptic situation clear without getting bogged down in description of the two previous books. Characters exist to drive this plot—with the twins and a couple of others well-developed and the rest edging into stereotype. The smashing climax is totally satisfying while anticipating the world-saving to come. Stock up—it should fly off the shelves! (Fiction. YA)