The Wailing Siren Mystery (The Hardy Boys Mystery Stories Book 30)

214 pp. 8vo. #30 in The Hardy Boys Mystery series. Beige tweed boards, light brown multipic endpapers, Bill Gillies jacket art. "Caught in their motorboat the Sleuth by a sudden storm at sea, Frank and Joe Hardy are relieved to see the lights of a yacht. But their SOS ignored. The shrill sound of a siren fills the night air and moments later a helicopter drops an object alongside the Sleuth: a wallet containing two thousand dollars! The next day, a truck carrying a shipment of high-powered rifles has been stolen. These two apparently unconnected events are clues in a tangle of mystery which turns out to be one of the detective brothers' most exciting adventures."