A mysterious cargo ship, seemingly without a crew, is sailing across the sea. It approaches a cruise liner, despite all warnings it isn't stopping, it wants to ram! Later on a few survivors of the liner, including the captain Ashland (George Kennedy), lie on a raft. The cargo ship looms behind them, the survivors not knowing this was the ship which caused their plight.
They board the ship, which is deserted and rusted and old. They discover it is a World War 2 German ship, they also discover it has a mind of it's own as the survivors are picked off one by one, including being grabbed by cranes, terrified to death in a shower of blood and being crushed in a net of corpses. Ashland, meanwhile, has donned the uniform of a German Navy captain and now calls the ship his own. Crenna (Trevor Marshall) and Nick (Nick Mancuso) discover the ship was used for Nazi tortures...
A superbly weird and macabre film. The derelict ship setting makes for a very eerie film. Often the best horrors have the threat coming from a faceless and unknowable entity, in this case it is an entire cargo ship! It makes little sense but is a great horror film.