The Radio Detectives Under the Sea

A pair of adventurous youths join adult companions on a tropical voyage that becomes a technical detective hunt, using wireless apparatus and a disguised submarine to investigate disappearances and suspicious undersea activity. The party encounters shipboard surprises, narrow escapes, underwater combat with a giant octopus, capture and imprisonment, and the startling reappearance of a formerly hostile man who shifts loyalties. Radio communication repeatedly enables rescues and covert tracking as the group pursues enemies across islands, coral cays, and the deep, resolving mysteries and settling debts through daring dives, clandestine pursuit, and coordinated teamwork.