The United States and the Soviet Union have both developed technology that can miniaturize matter by shrinking individual atoms, but only for a limited amount of time, depending on how small the item is miniaturized.
Amidst a storm, a boat is being piloted across the South China Sea by John Finnegan (Treat Williams). With him are his crewmen Joey "Tooch" Pantucci (Kevin J. O'Connor) and Joey's girlfriend Leila (Una Damon). Finnegan has been hired to transport a group of mercenaries, led by a man named Hanover (Wes Studi), to an undisclosed location in the middle of the ocean.
Après avoir quitté la Marine nationale française, Jacques-Yves Cousteau veut se lancer dans l'exploration sous-marine. En 1950, il loue le bateau Calypso à un riche britannique. Le « commandant » part alors aux quatre coins du Monde, avec sa femme Simone et notamment Albert « Bebert » Falco. Ses deux fils, Philippe Cousteau et Jean-Michel Cousteau, restent en pension... Quelques années plus tard, Philippe rejoint finalement l'équipe de son père, qui tourne une série de films documentaires financés par une chaîne de télévision américaine. Philippe étant sensibilisé à l'écologie à laquelle son père est insensible, il se brouille avec lui puis, alors que les affaires de Jacques-Yves périclitent, revient auprès de lui et le sensibilise à la protection des océans et des espèces animales menacées, donnant à la carrière de son père une nouvelle orientation et un nouveau départ.
DeepStar Six is a prototype deep-sea colony funded by the United States Navy with a collection of 11 military and civilian crew members in the last week of their six month tour. The brainchild of Dr. Van Gelder, the base is allowed to conduct its experiment on underwater colonization provided that he also oversee the installation of a nuclear missile storage platform nearby. Nearing the last days of his deadline, Van Gelder's plans are threatened when geologist Burciaga (Elya Baskin) discovers a massive cavern system at the installation site. Van Gelder orders the submarine crew to use depth charges to collapse the cavern, to the dismay of Dr. Scarpelli (Nia Peeples), who wants to preserve the cavern to study the potentially primordial ecosystem she suspects lies inside.
A strange giant "sea creature" has been rampaging the seas. The American naval ship Abraham Lincoln is sent to investigate, but is rammed by "the creature" which turns out to be The Nautilus, the fantastic submarine of the enigmatic Captain Nemo, and "Rudderless, the 'Abraham Lincoln' drifts on". Then, in "A strange rescue" he guides the sub to surface under those pitched overboard and his crew take them, including Professor Aronnax, and his daughter (who are French) below through a hatch in the surface of the deck. After they pledge not to escape, Nemo shows them the wonders of the underwater world, and even takes them hunting on the sea floor.
The new, state of the art nuclear submarine Seaview is on diving trials in the Arctic Ocean. The Seaview is designed and built by scientist and engineering genius Admiral Harriman Nelson (USN-Ret) (Walter Pidgeon). Captain Lee Crane (Robert Sterling) is the Seaview's Commanding Officer. One of the on-board observers is Dr. Susan Hiller (Joan Fontaine), studying crew-related stress. The mission includes being out of radio contact for 96 hours while under the Arctic ice cap, but the ice begins to crack and melt, with boulder-size pieces crashing into the ocean around the submarine. Surfacing, they discover fire burning in the sky. After the rescue of a scientist and his dog at Ice Floe Delta, Miguel Alvarez (Michael Ansara), the sub receives radio contact from Mission Director Inspector Bergan at the Bureau of Marine Exploration. He advises that a meteor shower pierced the Van Allen radiation belt causing it to catch fire, resulting in a world-threatening increase in heat all across the Earth. Nelson's on-board friend and scientist, retired Commodore Lucius Emery (Peter Lorre) concurs that it is possible. Bergan informs Nelson that the President wants him at a UN Emergency Scientific Meeting as soon as possible.
In 1959, United States Navy Rear Admiral Matt Sherman (Cary Grant), ComSubPac, boards the obsolete submarine USS Sea Tiger prior to her departure for the scrapyard. The first commanding officer of the Sea Tiger, Sherman begins reading his wartime personal logbook and recalling earlier events
A satellite reenters the atmosphere and ejects a capsule which parachutes to the Arctic, coordinates 85N 21W (approx 320 miles WNW of Nord, Greenland, in the Arctic Ocean ice pack). During an ice storm, a figure soon approaches, guided by a homing beacon, while a second person secretly watches from nearby.
On Christmas Eve, the submarine USS Copperfin, under the command of Captain Cassidy (Cary Grant), departs San Francisco on a secret mission. At sea, Cassidy opens his sealed orders, which direct him to proceed first to the Aleutian Islands to pick up meteorologist Raymond (John Ridgely), then to Tokyo Bay to obtain vital weather intelligence for the upcoming Doolittle Raid.
Mike and Tony Petrakis are Greek American father and son sponge diving entrepreneurs who find themselves in competition with the Rhys family, WASP fishermen who are prepared to resort to violence and even murder to maintain their established fishing grounds off the Gulf Coast of Florida. Run-ins between the two clans lead to an exchange of threats and all-out brawls. Further complications ensue when Tony Petrakis meets Gwyneth Rhys, and the two fall in love.
Two children, Jacques Mayol (Jean-Marc Barr) and Enzo Molinari (Jean Reno), have grown up on the Greek island of Amorgos in the 1960s. They challenge each other to collect a coin on the sea floor and Jacques loses. Later Jacques' father — who harvests shellfish from the seabed using a pump-supplied air hose and helmet — goes diving for shellfish. His breathing apparatus and rope gets caught and punctured by rocks on the reef and weighed down by water, he drowns. Jacques and Enzo can do nothing but watch in horror as he is killed.
Phaedra (Sophia Loren) is a poor Greek sponge diver who accidentally finds an ancient Greek statue of a boy riding a dolphin on the bottom of the Aegean Sea. Her efforts to sell it to the highest bidder lead her to two competing individuals - Dr. James Calder (Alan Ladd), an honest archaeologist with an academic's bankroll, and Victor Parmalee (Clifton Webb), a wealthy but unscrupulous art collector.
Marine scientists prepare to leave their underwater Oceanlab after an extended stay performing oceanographic research. An underwater earthquake interrupts their plans. Dr. Andrews (Walter Pidgeon) enlists experimental sub captain Adrien Blake (Ben Gazzara) to survey the damage and rescue the oceanauts. He brings along Chief Diver "Mack" MacKay (Ernest Borgnine) and Dr. Leah Jansen (Yvette Mimieux), fiancée of one of the scientists. Blake finds the lab has been ripped from its moorings and has tumbled down an unexplored, deep ocean trench, presumably intact. With the lab's reserve air supply dwindling, the team descends into the unexplored trench and finds an incredible ecosystem populated with monstrously over-sized fish. After surviving encounters with unfriendly denizens, they find the lab partially intact, the surviving scientists breathing from scuba tanks, and fending off giant, hungry eels. All but one of the scientists are rescued, and the submarine returns to the surface.
A World War II-era German submarine missing for 20 years is retrieved in the Bahamas by diver Mark Brittain, hired by the wealthy Rosa Lucchesi and her partner, Vic Rossiter, who have been searching for Spanish galleons.
In 1953, renowned French scientist Professor Montel (Victor Francen) goes missing. The authorities believe that he and four other scientists defected behind the Iron Curtain.