A swashbuckling fantasy trilogy trudges toward a formulaic conclusion in which a mythical city girds for a hopeless battle against overwhelming forces, hoping to provide sufficient diversion to cover the desperate quest of two unlikely heroes to destroy Ultimate Evil. Sound familiar? A bizarre alliance of retired gods, roguish pirates and extraordinary sea beasts defends Aelenium, the sketchily conceived starfish city, from monstrous kobalins of the deeps and the hordes of the cannibal king. Meanwhile, adolescent “polliwogs” Jolly and Munk acquire a problematic companion in Aina, erstwhile enemy—or is she?—of the terrible Maelstrom they must destroy. Cue gory battles, heroic sacrifices, encounters awesome and inexplicable. Just when All Seems Lost, the climactic confrontation turns upon the homely virtues of friendship. The piratical flourishes and campy charm of the previous titles are lost in the rush of plot. Key players careen from heroically noble to pettishly spiteful to inchoately alien—it’s tricky to tell heroes from villains. Not a bad series overall, but this volume is by-the-numbers. Purchase where interest in the first two demands. (Fantasy. 10-14)