Riley rescues her fellow islanders, human and otherwise, from fairies and their curses in this series closeout.To finish off, O'Hearn adds two new strife-ridden realms to the hidden isle of Atlantis-one an undersea cavern where dwell two camps of spell-singing merfolk and the other a quarter of the hidden island belonging to the fairy folk. She sends her peace-loving protagonist to both for two brief but savage climactic battles. What's really at war here is the author's chosen plotline juxtaposed against her strenuous efforts to downplay its implicit violence. Despite apparently seeking to distract readers by adding flower-strewing pixies and polka-dot hippos with fairy heads to the crook-horned unicorn colt, adorable talking koala, and other plushy members of the teeming cast, she trots in evil fairies who can only be deprived of their powers by having their wings ripped off, for instance. And then, when the ripping is done, why not gather for a joyous feast? Moreover, doubtless to the disappointment of readers who like to see the fighting as it happens rather than just be told about it later, she forces the finale of the second battle and the death of a vicious predator to occur entirely offstage. Still, by the end, not only have all the magical, mythical, and hybrid human-animal Atlanteans come together in harmony, but a broken contraceptive spell allows the nearly extinct gargoyles to have baby gargoyles again. Baby gargoyles!Muddles through to a properly happy ending. (map) (Fantasy. 9-12)