Since the Changes began, machines have been anathema in England except, somehow, to Geoffrey Tinker; after five years as the Weymouth weathermonger, he has been caught fiddling with a motor boat, bludgeoned, and marooned on a rock with his sister Sally. The blow has obliterated his memory of the past five years but not his power to manipulate the weather, and they are soon safe with earlier English refugees in France. But to the other Western powers, ""the English phenomenon"" appears as a malignancy: because Jeff and Sally seem to be immune, they must return to discover its source. The scheme contrived by tyrannical General Turville calls for their covert return by motorless boat, then the activation of a long-cocooned 1909 Rolls Royce Silver Ghost for a dash across to the Welsh mountains, source of the most erratic weather. It is a brilliant episode: Jeff (who's 16) driving the Silver Ghost, fitted with a battering ram, through the flocks and toll gates, around the potholes and cursing people of an England which in five years has lapsed into the Dark Ages. . . until a dark cloud bears down on them, one that Jeff isn't strong enough to counter, and the Rolls is demolished by a thunderbolt. This is the work of the Necromancer, otherwise old friend Merlin--a bit of a disappointment, really, but attended by a flustery sort of Frankenstein who's splendid foil. Moments after the cataclysm immuring Merlin, jets appear, bringing the General, mechanical efficiency, unfeeling calculation. . . . One might speculate about the theme (is every British author at heart an Edwardian if not a Luddite? is every garden plot Merlin's graveyard?) but the story, ingeniously conceived and vividly personalized, brooks few reservations.