An altogether different sort of undertaking from the author of last year's strong Machine Gunners, this is a contemporary family fantasy set on the North-umbrian coast where the medieval, wizard-like St. Cuthbert lived and died and, purportedly, routed a band of Viking raiders. It's also where Mike's pedantic Cambridge professor father and his grating second wife, Beth and Sally's mother, take the family to vacation in the old house left to them by an eccentric uncle. On the property is an ancient boat which turns out to be a time ship, repeatedly taking the children (just as it had the uncle) back to Cuddy's time. Mike, gungho for adventure at first, comes to fear the encounters, small Sally is drawn to them by a frightening power, and devout Beth, in rescuing her sister, makes a more genuine psychic contact with the saint. But it is Bertrand, the doggedly rationalistic father, who is devastated--and, literally, sea-changed--by the dramatic manifestations of Cuddy's power. Westall's merciless and unequivocal argument for the sort of unseen reality that the Cuthbert legend represents is unduly heavy and not likely to disarm other, unconverted Bertrands; but his plotting will keep them in thrall. The bickering parents are unpleasantly real enough to win identification with their offspring, and the compellingly evoked coastal locale makes the bridging of centuries there seem entirely natural.