The film, a parody of the novel Twenty Thousand Leagues Under the Sea by Jules Verne, follows a fisherman, Yves, who dreams of traveling by submarine to the bottom of the ocean, where he encounters both realistic and fanciful sea creatures, including a chorus of naiads played by dancers from the Théâtre du Châtelet.
When a little girl goes missing in the woods, her parents are at a loss as to what to do. To their great relief, a boy with a sixth sense shows the way to the girl using his psychic abilities.
Many demonstrations of the art of Jiu Jitsu are given, and as evidence that this is not a passing fad intended only for the amusement of the public there is illustrated in very thrilling manner how several footpads follow two girls and then in a deserted section of the road make an attack, which is successfully foiled and the perpetrators taken into custody.
The scene of the drama is a block of modern flats. Many of the residents are away at a dance, and the janitor and his staff decide upon a jollification of their own.