The Seaview encounters a strange structure on the sea floor. Investigating they discover a German submarine from WW2. Surviving Germans on-board think the war is still being fought. And they have weapons on-board of unimaginable destructive power.

While on routine patrol the Seaview begins to hear strange noises coming from an undersea canyon. Investigating they discover the source of the noise and the power behind the destruction of a British fleet in the area 200 years before.