With two mysteries to solve, Frank and Joe must climb aboard their
iceboat the Sea Gull to reach Cabin Island, where a belligerent
stranger orders them off. Sabotage to the boat, danger to themselves,
and a ghostly prowler do not daunt the Hardy boys in their search for
Johnny Jefferson and for clues to stolen antique medals. How the teenage
investigators outwit a ruthless foe and succeed in solving both
mysteries makes for mounting suspense in this brisk-paced adventure.