An unknown sea monster has been destroying and damaging warships of different countries for the last two years; those of them who get to the port find giant triangular holes in the sides.

Famous for his work on the mysteries of the depths of the sea, the French professor Pierre Aronax on the day of his wedding receives an invitation to join the punitive expedition and accepts it.

The professor, his servant Conseil and Ned Land whaler fall overboard onto a submarine, which they initially mistake for a giant dangerous animal.

He finds François, a young sailor-Frenchman in the crew of the ship, at one time picked up by the captain in the sea and left on the Nautilus voluntarily.

Thanks to the education received in Europe, Prince Dakkar designed and organized the construction of an underwater ship of fantastic qualities for his time and left with some of his faithful friends to sea.

The English military frigate, armed with powerful cannons, depth charges and moving at the same speed as the Nautilus, pursues Captain Nemo on the way to Crete.

Unlike Nemo, who knows his enemy exactly, he only foresees that he had already met with the captain of the submarine ship before, but he is absolutely sure that the Nautilus must be destroyed, since whenever it appears, the national liberation movement increases.

Through titanic efforts of the entire team, including Professor, Conseil and Land, they manage to manually disassemble the dam and leave the dangerous shelter.

To deceive the British, Nemo explodes tanks with a combustible substance in the water, so as to simulate the destruction of the ship, and the Nautilus escapes from pursuit.

In the final shots Professor Aronax is at home, in the company of his wife and Conseil, giving an interview to a correspondent and talks about his plans for writing a book about an unusual subaquatic journey.