In the second half of the 19th century, in the seas and oceans, sailors began to come across an unusual object - a luminous spindle-shaped object, surpassing the speed and size of a whale. Newspapers, and after them scientists all over the world, became interested in the “sea monster.”

But fate turned out to be merciful only to Professor Aronnax, who, with his servant Conseil and harpooner Ned Land, by chance (or the author, which is essentially the same thing) the same), find themselves on board an extraordinary and only submarine in the world. The captain and crew of the boat turned out to be not monsters at all and the heroes experienced many dangerous and amazing adventures, traveling around the world 20 thousand leagues under water.