The Wailing Siren Mystery

Frank and Joe Hardy find themselves in a perilous situation when their motorboat breaks down during a storm at sea. After a mysterious yacht ignores their distress call and a helicopter drops a wallet full of cash, the boys are drawn into a new case. The theft of high-powered rifles from their friend Chet Morton's uncle soon connects to these strange events, leading the young detectives on one of their most thrilling adventures.