The third case for Beantown's clever Chameleon the Spy pits him against two oily impostors, Prince and Princess Ookcray--who, understandably, take the localites for dummies (who don't even understand Pig Latin). Only Chameleon, in the Mayor's office when the pair arrive, asks awkward questions. The island they profess to come from isn't, he notes, on the globe--because, allegedly, ""Maps are made during Monsoon season. And during Monsoon season, the Isle of Unksay is under water."" But Chameleon isn't through: ""Doesn't everything in your castle get wet?"" What happens, guessably, is ""A magnificent Beantown Ball, in honour of Your Royal Highnesses? And there, inescapably, everyone's jewels do start to disappear--including Princess Ookcray's. . . which turn up in the Mayor's pocket! You may know who-dun-it, and how--but, to catch the thieves (and exonerate the Mayor), Chameleon needs an assist from the airport X-ray monitor. Scripted with the usual shrieks and other sounds (WHISK! CLANK! OUCH!), punctuated with the usual crafty drawings of every plot development: a special delight for early, good readers.