Dead In The Water
During the early years of World War II, the legendary and lethal Nazi U-boats spread terror from beneath the sea. Now, more than fifty years later, on a salvage operation off the coast of Florida, the Hardys plunge into the rusting hull of one of those awesome submarines...and discover that the terror still lives!
When Alvin Mann, leader of the salvage operation, vanishes without a trace, Frank and Joe vow to rescue him -- and find out what deadly secret lies hidden on the ocean bottom. But first they'll have to confront a brutal adversary armed with knives, spearguns, and more -- an enemy determined to blow them out of the water!