Andre St Avit of the French Foreign Legion is discovered unconscious in the African desert. He claims he stumbled upon the lost kingdom of Atlantis, ruled by the beautiful Queen Antinea, who drove him to commit murder.
Un ancien officier de la légion étrangère, Morhange, part à la recherche de son ami Saint Avit perdu dans le désert du Sahara, duquel il reçoit un étrange dessin gravé d'un symbole en forme de croix et du nom « Antinea ».
In 1911, two French officers, Capitaine Morhange and Lieutenant Saint-Avit, become lost in the Sahara desert and discover the legendary kingdom of Atlantis, ruled by its ageless queen Antinéa. They become the latest in a line of captives whom she has taken as lovers, and who are killed and embalmed in gold after she has tired of them. Morhange however, already grieving for a lost love and planning to take holy orders, is indifferent to Antinéa's advances and rejects her. Angered and humiliated, she exploits the jealousy of his friend Saint-Avit and incites him to kill Morhange. Appalled by what he has done, Saint-Avit is helped to escape by Antinéa's secretary Tanit-Zerga, and after nearly dying in the desert from thirst and exhaustion, he is found by a patrol of soldiers. Saint-Avit returns to Paris and tries to resume his life, but he is unable to forget Antinéa. Three years later he returns to the desert and sets out to find her kingdom again, accompanied by another officer to whom he has told his story.
Wanda Saknussemm (Ireland) is a nerdy social misfit with large glasses and a squeaky voice who lives in Los Angeles and works at a diner. After being dumped by her boyfriend for "not having a sense of adventure", Wanda is informed by a letter that her father, an archaeologist, has died. She flies to northern Africa and while going through her father's belongings, she finds his notes about Atlantis, apparently an alien ship that crashed millennia ago and sank into the center of the Earth. Wanda comes across a chamber beneath her father's apartment and accidentally sets off a chain of events that ultimately cause her to fall into a deep hole.
In the Atlantic Ocean, the USS California submarine picks up incoming human-like threats approaching the sub by sonar. The sub is attacked, leaving the entire crew dead by the invading hostiles. At S.T.A.R. Labs' Justice League headquarters, Cyborg is given news by Colonel Steve Trevor over the sunken sub. Cyborg decides to check it himself, deciding against Trevor's idea of calling the other superheroes, as he puts it "there is no Justice League".
It is the year 1891 and a military doctor, Lieutenant Claude de Ross (Claudio Cassinelli) a survivor of not one, but two shipwrecks, washes ashore on a mysterious, uncharted Caribbean island along with a handful of convicts. When several of these convicts meet unfortunate ends at the hands of the titular fishmen, Claude and the other survivors flee into the jungle, only to encounter the sadistic Edmond Rackham (Richard Johnson) and his beautiful captive Amanda Marvin (Barbara Bach).
The story opens with a transmission received by the White House from the renegade Professor Cunningham, who threatens Washington DC with nuclear destruction from a missile fired from his submarine Raven. His extortion demand is one billion dollars in gold bullion. To demonstrate his capability he blows up small island with the Raven's 'Delta beam'. Cunningham, bespectacled and cardigan-clad, is assisted by various androids including a large silver-headed one known as Tor.
Around the beginning of the 20th century, British archaeologist Professor Aitken and his son, Charles, have chartered a ship called the Texas Rose to take them out to sea, where they plan to dive underwater in a diving bell designed by engineer Greg Collinson. Although everyone aboard the ship, including Greg, thinks that the Professors Aitken are just going to look at fish, Charles and his father are secretly searching for proof of the existence of the lost city of Atlantis. He and Greg find it on their first dive, and then some. First, they are attacked by a reptilian sea monster, which comes through the bottom of the diving bell, but Greg is able to fend it off by sticking a live wire into its mouth, electrocuting it.
After the decline in Atlantean culture following the sinking, Kida (Cree Summer), now Queen, and married to Milo Thatch (James Arnold Taylor), is using the heart of Atlantis to restore her city's former glory. Suddenly, Milo's comrades and Mr. Whitmore (John Mahoney) arrive in Atlantis; while their arrival is unexpected, the Atlanteans welcome their old friends. Unfortunately, they have come to inform them of mysterious creature causing trouble on the surface. They arrive in Norway and discover that the mysterious problem is actually the creature known as the Kraken, which had been attacking shipping freighters and taking their cargo to a cliffside village. At first they presume it to be an ancient Atlantean war machine gone rogue (like the Leviathan from the previous film), but they discover that the town magistrate, Edgar Volgud (Clancy Brown), seems to be controlling the Kraken. They soon learn, though, that the Kraken itself is the master, having made a deal with Volgud. When they blow up the Kraken, the man disintegrates and restores the spirit of the village.
The plot revolves around the main character "Crash" Corrigan trying to stop an evil tyrant ruler of Atlantis from conquering the lost continent and then the entire upper world.
In Edinburgh, Scotland, in 1880, Professor Sir Oliver Lindenbrook (James Mason), a geologist at the University of Edinburgh, is given a piece of volcanic rock by his admiring student, Alec McEwan (Pat Boone). Deciding that the rock is unusually heavy, Lindenbrook, mostly thanks to the carelessness of his lab assistant, Mr. Paisley (Ben Wright), discovers a plumb bob inside bearing a cryptic inscription. Lindenbrook and Alec discover that it was left by a scientist named Arne Saknussemm, who had, almost 300 years earlier, found a passage to the center of the Earth. After translating the message, Lindenbrook immediately sets off with Alec to follow in the Icelandic pioneer's footsteps.
It has been four years since the events of the first movie. Seventeen-year-old Sean Anderson (Josh Hutcherson) is caught by the police after a brief chase on his dirtbike which ended with him driving into a swimming pool while trying to evade them. Minutes later, his stepfather Hank (Dwayne Johnson) arrives where a police officer (Stephen Caudill) who is friends with Hank tells him that Sean had broken into a remote satellite research center. The police officer also tells Hank that he has talked Mr. and Mrs. McGillicutty (the owners of the swimming pool) out of pressing charges. Hank takes Sean home where his mother Elizabeth (Kristin Davis) is not pleased with his actions or the fact that he and Hank don't get along well.