Missing: One fabulous, jewel-encrusted belt, once owned by the ancient emperors of Japan. But when The Three Investigators offer their detective services to an official at the Peterson Museum, he throws their business card to the floor in disgust. Chasing thieves is work for men -- not boys, he tells them. Then a strange twist of fate brings Jupe, Pete and Bob back on the case. Soon they're surrounded by master criminals -- who will stop at nothing to keep their stolen fortune!