Four men, a woman and her child are rescued by Captain Nemo (Robert Ryan) when their ship – en route from London to America during the civil war – sinks during a storm.
The survivors are US Senator Robert Fraser (Chuck Connors); widow Helena Beckett (Nanette Newman); her young boy, Phillip (Christopher Hartstone); a twitchy claustrophobic chap named Lomax (Allan Cuthbertson); and two bumbling crooks – Barnaby (Bill Fraser) and Swallow (Kenneth Connor) – who provide the film’s comic relief.
Nemo takes the survivors to his utopian domed city 10,000 fathoms below the surface of the sea and won’t allow the new arrivals to return home to the surface for fear that they will reveal the existence of his amazing metropolis to the warring nations above.
Senator Fraser becomes involved in a romance with Mala (Lucianna Paluzzi), which enrages Joab (John Turner).
Nemo becomes a kindly father-figure to young Phillip and develops a close friendship with the headstrong Helena. Eventually offered the choice to betray Nemo and leave the undersea city, or stay with Nemo and form an ad hoc family, Helena chooses to remain.
Meanwhile, a giant manta ray named Mobula threatens the city until Fraser becomes a hero after dispatching the murderous beast while in command of Nautilus. But Fraser is plotting to escape aboard a brand new Nautilus #2 with the help of the treacherous Joab and the avaricious Barnaby.
Captain Nemo
Robert Ryan
Senator Robert Fraser
Chuck Connors
Helena Beckett
Nanette Newman
Mala
Luciana Paluzzi
Joab
John Turner
Barnaby Bath
Bill Fraser
Swallow Bath
Kenneth Connor
Lomax
Allan Cuthbertson
Phillip Beckett
Christopher Hartstone
Adam
Ian Ramsey
Skipper
John J. Moore
Navigator
Vincent Harding
Director
James Hill
