A German professor, living for some reason in London, takes on some adventurous and rich Englishmen, and sets off with them in an airship that is made of a material so light that it can rise vertically into the air if you pump out some of the air in its ballast tanks. It can also plunge into the depths of the ocean, because this special material, aetherium, is so strong that it can withstand water pressure to a great depth. In this vehicle they visit the North Pole, having several adventures on the way, including finding the remains of a Viking ship. They visit a region in Africa where they depose the existing King and install a King who is more to their taste. Then they head off for Mount Everest, where they become the first persons to sit on the summit. Here again they have more adventures of a perilous kind.