A boy with a fabulous uncle has adventures with an illogical logic which makes the solving of an international jewel theft quite entertaining. During a visit to his Uncle Bounce, a wealthy and jovial old man whose hobby it is to travel, collect rare objects and turn them over to American museums, young Casey is told, on his arrival, of a peculiar chain of events taking place in Uncle Bounce's museum piece of a house. Unhesitatingly, Casey plunges into the role of detective. He and his pal Ben run into a strange array of characters- as a Maharaja's son comes from India, as Philomon the valet gets shadier and shadier, as Perch, the Jeevesian butler, turns out to be a government man after a gang who have been using Uncle Bounce as an innocent front through which to smuggle jewels into the U.S.A.