A ship with three passengers lands on Jupiter so that they find out as much as possible about the Jovians and their weapons. Jupiter methodically lavished threats to take over the entire solar system and the Universe at the same time. The Jovian army tried to destroy the aliens, but nothing came of it. And when the local military saw that the earthlings were freely sticking their hands into the molten metal, lifting large loads, not eating, not sleeping and not getting tired, they became thoughtful...