Second in the projected Pendragon Quartet, this flabby adventure owes nothing to Camelot but the name. Previously, jock Bobby Pendragon, 14, discovered that he’s a Traveler, responsible for preventing chaos across the dimensions. Now, with his mentor, Uncle Press, Bobby travels to the water world of Cloral in pursuit of interdimensional baddie Saint Dane. Teaming up with the devil-may-care Vo Spader, they discover that the food supply has been poisoned, threatening to destroy Cloral’s utopian society. Their only hope is to locate the mythical city of Faar (think Atlantis), source of Cloral’s civilization, sunk long ago beneath the endless sea. Meanwhile, back on Second Earth, Bobby’s friends Courtney and Mark run into their own spot of trouble when the school bully blackmails Mark into turning over the journals in which Bobby recounts his adventures. MacHale (The Merchant of Death, not reviewed) displays a flair for action-packed pacing, and the final cliffhanger would be an effective hook into the next title—if not for the unrelieved flatness of both characters and setting. MacHale’s world-building is devoid of either logic or wonder, and he substitutes irritating invented slang (“tum-tigger,” “natty-do,” “hobey-ho”) for developing Spader’s personality. Bobby’s own voice also grates unconvincing, describing every new experience as either “bizarro” or “cool.” Bobby’s constant puzzlement over why he was chosen to be a Traveler is likely to be shared by readers, who will see little of the likable charm or grand destiny to which the other characters constantly allude. Hobey-hum. (Science fiction. 10+)