By a writer with a record highly readable and truly adult adventures for young readers (The Port of Missing Men, The Sunken Forest), a jewel mystery theft that moves with the sleight of hand quickness needed to solve it. A small but fancy eastern resort and a nearby sanitarium background the story set around Richard and Johnny, two young brothers spending the summer with the Eastrum family not far from the resort-Ishno Lake. The people Richard and Johnny meet are in small time show business. There are the magician Mr. Drayton, and his daughter Belinda, also at the Eastrum's, who are waiting for nearly cured Mrs. Drayton's discharge from the sanitarium. The Drayton's badgering Aunt Mabel arrives for a stay at Ishno and objects when a proposed performance of magic at the resort may shed light on her show-lady past. The show is finally given. Then Richard's suspicions of Aunt Mabel's queer chauffeur flower when a brazen theft is committed during the performance and the culprit found to be the chauffeur's brother posing as sanitarium patient. Suspense all the way.