$200
DIXON, Franklin W.
[214] pp.
Grosset & Dunlap
1952
Publication year coincides w/ The Secret of Wildcat Swamp last title on front flap
7 1/2" x 5 3/8"
Jacket design by Bill Gillies
Endpapers by Gretta
Their SOS ignored by a strange yacht in a storm, the Hardy Boys find a wallet alongside their speedboat, apparently dropped from a helicopter, containing two thousand dollars, and are launched into a mystery involving diverse clues. This includes finding out who kidnapped Jack Wayne and took his plane, and where the wailing siren is coming from.