Off the coast of Alaska, oceanographer Emma MacNeil (Deborah Gibson) is studying the migration patterns of whales aboard an experimental submarine she took without permission from her employer. Meanwhile, a military helicopter drops experimental sonar transmitters into the water, causing a pod of whales to go out of control and start ramming a nearby glacier. In the chaos, the helicopter crashes into the glacier, and the combined damage breaks the glacier open, thawing two hibernating, prehistoric creatures. MacNeil narrowly avoids destruction as, unknown to her, a giant shark and octopus are freed. Some time later, a drilling platform off the coast of Japan is attacked by the octopus, which has tentacles large enough to wrap around the entire structure. After returning to Point Dume, California, MacNeil investigates the corpse of a beached whale covered with many bloody wounds. Her employer Dick Richie (Mark Hengst) believes them to be from a tanker propeller, but MacNeil insists they appear to be from a creature. Later, she extracts what appears to be a shark’s tooth from one of the wounds. Elsewhere, the huge shark leaps tens of thousands of feet into the air from the ocean and attacks a commercial aircraft, forcing it to crash into the water.
The Royal Navy is concerned about constant attacks on convoys by German submarines and having to keep "half the fleet" watching for the German battleship Tirpitz. The Tirpitz is 60 miles from the sea inside a Norwegian fjord and attempts by the Royal Air Force to sink her have failed. Commander Fraser (Mills) is determined to prove that an attack by human torpedoes is practical, despite scepticism from the higher echelons that such an operation would be feasible.
Lieutenant Taylor (John Mills) and the rest of the crew of the submarine Sea Tiger are given a week's leave after an unsuccessful patrol. Hobson (Eric Portman) goes home to save his marriage, while a reluctant Corrigan (Niall MacGinnis) heads off to his wedding. Then the crew are called back to duty, much to Corrigan's relief, though he later has second thoughts. Sea Tiger is assigned the top secret mission of sinking Nazi Germany's new battleship, the Brandenburg, before she enters the Kiel Canal to begin sea trials in the Baltic Sea.
American David Ross (William Holden), a former tugboat captain now in the Canadian army, is hastily commissioned in the Royal Navy and assigned to rotating command of W88, a double-crewed rescue tug then in dry dock due to battle damage. His predecessor was a suicide. The slow, poorly armed tugboats bring in "lame ducks," freighters crippled near England by German attacks. The main danger is from U-boats and aircraft.
During 1964, in the months following World War III, the conflict has devastated the northern hemisphere, polluting the atmosphere with nuclear fallout, killing all life there. Air currents are slowly carrying the fallout south; the only areas still habitable are in the far reaches of the southern hemisphere.
The film begins with Commander Bolton and a few surviving crew members of his 50-man submarine Gauntlet swimming ashore after unsuccessfully attacking German battleship Lindendorf. After a review, Captain Bolton is cleared of any wrongdoing and placed in charge of a small group of experimental X class submarines. His mission is to quickly train crews to man the submarines and sink the Lindendorf while it is hidden away in a Norwegian fiord.
The legendary empire of the lost continent of Mu reappears to threaten the world with domination. While countries unite to resist, an isolated World War II Captain has created the greatest warship ever seen, and possibly the surface world's only defense.
Three very likeable losers fail while they pursue individual goals. Roland Darbont (Lino Ventura) is an inventor who has designed his own engine. Manu Borelli (Alain Delon) on the other hand is a pilot who prepares a spectacular stunt. Both of them are running tests on Darbont's premises when they are joined by Laetitia Weiss (Joanna Shimkus), an artist who builds abstract statues from scrap metal. They nourish each other's hopes and learn to get along with each other.
Three men (Dr. Ken Tashiro, Dr. Jules Masson, and Perry Lawton) are trapped in a bathysphere due to seismic activity. They are rescued by the crew of the supersubmarine Alpha, captained by Craig Mackenzie (Cotten), who they learn is over 200 years old (and that the Alpha was launched in the early 19th century). Mackenzie takes them to Latitude Zero to deal with the serious injuries of Dr Masson. While returning to Latitude Zero, they are attacked by a rival supersubmarine, the Black Shark, captained by Kuroi, who works for a rival of Mackenzie, Malic, who is also over 200 years old and has a base at Blood Rock.
Yves, a fisherman, comes home after a tiring day of fishing and soon falls asleep. In his dream, he is visited by the Fairy of the Ocean, who leads him to a submarine. Yves is made Lieutenant-in-Command and sets off on a submarine voyage.
The plot revolved around the recent incident involving the German commander Baron von Luxburg who sank an Argentine ship intending to frame the Entente for the act. Reports from survivors helped everyone to realize what had truly happened.
L'équipage d'un sous-marin allemand sous le commandement du capitaine-lieutenant Liers est de nouveau en mer pendant la Première Guerre mondiale. Les hommes ont eu du mal à dire au revoir à leurs compagnes, mais le devoir les appelle. La mère de Liers a déjà perdu deux fils dans la guerre et redoute sa disparition.