Boy Scouts in the North Sea; Or, The Mystery of a Sub

Four young Scouts traveling through wartime waters become embroiled in a maritime mystery after a package vanishes and reports emerge of a submarine identified as U-13 sinking ships. They secure passage on a small vessel, confront suspicious characters, and observe submarine activity and a fleet of undersea craft. The plot moves through daring episodes—diving on wrecks, shipwreck and rescue, mistaken identities, and covert visits—mixing action with investigation as the boys piece together clues that reveal the origins, methods, and explanations behind the submarine sightings and related sabotage.